Optical Systems for the Microscope

General remarks

Planapochromats Phase-contrast obiectives

A few wordson the workingprinciple of the microscope

P O L Zo b i e c t i v e s

4 Parfocalizationof objectivesandeyepieces10 Appropriateselection o f i n i t i a lm a g n i f i c a t i o n s of objectivesand eyepieces 12 F i e l do f v i e wa n d v i e w i n ga n g l e 14 Correctionof aberrations 16 The coverglassand its importancefor i m a g eq u a l i t yi n t h e m i c r o s c o p e The immersionmethod 20

51 52

54 56 UD Achromats 57 Special-purposeobjectives 58 ULTRAFLUARS Jamin-Lebedeff transmitted-light interferenceequipment 59 microscopy 60 Objectivesfor reflected-light E P I P L A NH D o b i e c t i v e s 61 62 E P I P L A No

63 64

EPIPLANPOL objectives

65 ZEISSobiectives Classificationof objectives Achromats Planachromats NEOFLUARS Planapochromats ULTRAFLUARS Obiectivemounts ZEISSobjectivesfor photomicrography LUMINARS

23

25 26 27 27

68

Photomicrographic objectives LUMINARS w i t h i r i sd i a p h r a g m Epi-LUMINARS

69 71

28 29 32

Eyepieces C-typeand Kpl eyepieces Eyepiecesfor spectaclewearers Eyepiecesfor micrometerdisks Micrometerdisks Object markerwith diamondtip

72 73

36

Pointereyepieces

74 75 76 77 78

Eyepiecefor stereomicroscopes

80

42

Microprojectioneyepieces

B1

46

Special-purpose eyepieces Grain-sizedisks accordingto ASTM E and VDE h standards

82

Intermediate systemschanging

Stagemicrometers

M ZEISScondensers D a r k -ife l d i l l u m i n a t i o n

EPIP Pho Antifleximmersionobjectives

Integrating micrometer disks Doubleeyepiecewith pointer Centeringtelescope,Klein magnifier, ctrosco

84 86 86

Ing

systems NEOFLUARS

Condensers

88 89

remarks General A few words on the working principle lf objectsor detailsare to be seen clearly, of the microscope a sufficientlylarge image must be formed on the retina of the eye. A measureof the size o f t h i s i m a g e - w h i c hc a n n o tb e m e a s u r e dd i r e c t l y - i s t h e s o - c a l l e da n g l eo f v i e w .I n m a n y c a s e st h i s i s s o s m a l lt h a t t h e d e s i r e dc l a r i t y c a n n o l o n g e rb e a c h i e v e dT. o o b t a i ng r e a t e r clearness,means must thereforebe used to i n c r e a s et h e v i e w i n g a n g l e a n d t h u s t h e i m a o ef o r m e do n t h e r e t i n a . fhe simplest solution consists in approachingthe eye as closelyto the object as p o s s i b l e .T h i s . h o w e v e r ,i s f e a s i b l eo n l y t o a c e r t a i ne x t e n tb e c a u s eo f t h e l i m i t e da b i l i t y of the eye to accommodate.To overcome this difficultywe have to avail ourselvesof lensesor lens systems.The effectof such an auxiliarymeansis, in each case,that the object located a short distance in front of the eye-or even an image of such an object-is imagedat a greaterviewingangle and a sufficient distancefrom the eye to allow observation without any particularstress on our m e c h a n i s mo f a c c o m m o d a t i o n . T h e a i d u s u a l l ye m p l o y e df o r t h i s p u r p o s e is an ordinaryconverginglens of sufficiently , h i c hw i l lf o r m a m a g n iife d s h o r tf o c a ll e n g t hw image of an object located in its focal plane at a distancefar enough for the eye looking t h r o u g ht h e l e n s t o v i e w i t w i t h o u td i f f i c u l t y . T h e e y e w i l l t h e ns e et h e o b j e c tu n d e ra w i d e r viewing angle as if it were viewed from a normal distance.Such a lens is called a magnifier.lts magnificationis definedas the relationshipbetweenthe tangentfunctionsof the two viewing angles,a certainvalue having been adoptedas the normalviewingdist a n c e ,v i z . 2 5 0m m . T h i s i s t h e s o - c a l l e dd i s tance of distinctvision. Using this value,we o b t a i nf o r t h e n u m e r i c avl a l u eV Lo f t h e m a g n i ficationof a magnifierof focal lengthfL: ,r, - -250 v L

-

f ,

lf higher magnificationsare required, simplelensesare no longersufficient.In this case,the requirementsto be made of image quality can only be satisfiedby lens combinations. However,the magnificationwhich can be achieved in a single magnification stage, as in a magnifier,is limited because technicalproblemsonly allowthefocal length to be reducedto a certaindegree:the lenses haveto be curvedever moresteeplyand their diametersthus become smallerand smaller. This results in difficultiesnot only in manuf a c t u r i n g ,b u t p r i m a r i l yi n u s i n g t h e m : t h e viewing distance is greatly reduced, the image brightnessis low and the visual field small. These disadvantagescan be overcomeif two successiveimage-formingsystems are used as is the case in the compound microscope: The first stage of image formation consists of a lens system,the microscopeobjective, located close to the object, which forms a real and magnifiedaerial image of the object, usually at a certain distance from the latter. The relationshipbetween image size and object size,the scale of the image M,ni, is governed by optical laws and is represented by the relationshipof the separation between the image and the primary focal point of the objective,which is called the "optical tube length t", and the objective focal lengthfoui,viz. M o b i=

fobi

The contentof this aerialimageformedby the objective,i. e. the detail of fine object structuresit contains,however,has nothing to do with the scale at which the objective reproducesthe object. On the contrary-as Abbel was the first to prove-it dependsnot

only on the wavelengthof the light used for observation,but primarilyon the light-admitting propertiesof the objective. These are determinedby the apertureangleof the cone of rays from the pencil originatingat the object, which is able to enter the instrument through the aperture of the objective. The measure of this angle is-likewise since Abbe-the numericalvalue of the sine function of half the apertureangle. lf the pencil originating at the object does not pass through air before it reachesthe objective, but through another medium of differentrefractive index, the angle must be multiplied by this index. Becauseof its importancefor image formation in the microscope,Abbe coined the term numerical aperture for the product of the sine of half the aperture angle and refractiveindex. Thus if this rerm is abbreviatedN.A.,as is customaryin microscopy, and o insertedfor half the aperture angle,then we have N.A,:n.sino With regardto the magnifiedimageformed by a microscopeobjectiveit must be noted that two adjacentobject detailswill only be separated,or resolvedas it is called in optical language,if the expression

)'

)'

>a > N . A .: - : 2 N . A .

applieswith regardto their separationd. Consequently, the magnitudeof the separation d to be resolvedis always betweenthe limits ), I ano *-A2NA I II u s t r a t i o n : l l l u m i n a t i n gc o n e m a d e v i s i b l e . The cone of light varies as a function of the numerical aperture.

I Ernst Abbe (1840-1905), physicist and professorat Jena. From 1867worked for the ZEISS Optical Works. Became a Dartnerin t h e c o m p a n yi n 1 8 7 5P . i o n e e ro f m i c r o s c o p ec o n s t r u c t i o nE. s l a b l i s h e dt h e Z E I S SF o u n d a t i o n .

Resolvingpoweral J"= 550nm Table 1 Objective aperture

0.10 0.30 0.65 0.95 1.25 1.40

Separationd (p) N.A. 5.5 1.83 0.84 0.58 0.44 0.39

2 N.A. 2.75

0.92 0.42

0.29 0.22

0.20

An importantfact which is frequentlyoverlooked is that nearthe lirnit of resolutiongiven by the aboveformulait is exclusivelythe distance betweenthe object details which is reproduced correctly. Nothing can be said about their shape. To reproduceobject configurationswith a reasonabledegreeof similarity, we must remain considerably-by a factor of about 5 to 1O-above the limit of resolutionfor the detail in question. The second stage of image formation in the compound microscope is exclusively designedto spread the image produced by the first stage so that all detailscan be conveniently recognized by the eye. For this purposethe aerial image formed by the objective is viewed through a lens systemacting like a magnifierand called the eyepiece. It is natural that even the highest eyepiece magnificationcannot show the eye more than the aerial image in accordance with the resolving power of the objective. There is thus no point using a higher eyepiece magnificationthan is requiredto make the resolveddetailof the aerialimagevisible. Abbe realizedthat it was sufficientto use a total magnificationof the objective-eyepiece system of 500 to 1000x ihe objectiveaperture. He coined the term usefulmagnification

for thisrange. The total magnificatiohVmicris just the p r o d u c to f t h e s c a l eo f t h e a e r i a li m a g eM o o i produced by the objectiveand the eyepiece magnificationVoct, namely 250

Vmicr:+

focI

O n t h e b a s i so f t h i s f o r m u l aw e o b t a i nf o r the total focal length of a compound microscope 250 250 \/ v m r c r-

f"b . f""

-

f micr

t , lmicr:

E y e p ie c e

Intermediate lmage

Objective

Specimen Schematic drawing of the light path in the microscope

fobi ' focl 1

A c l o s e rl o o ka t t h i sf o r m u l ac l e a r l ys h o w s the advantageswhich the compoundsystem has over the simplemagnifyingsystem: D u e t o t h e p o s s i b i l i t yo f c o m b i n a t i o na, multitude of total focal lengths can be achievedwith only a few elementsof different focallength. Since the focal lengths of the different components remain large as compared to the focal length of the overall system, it is possible by appropriate selection of the formerto obtain practicallyany desiredshort overallfocal length. This meansno lessthan that the magnifyingpower of a microscopeis a c t u a l l yu n l i m i t e d .T h a t t h i s u n l i m i t e dm a g n i f y i n gp o w e r c a n n o t b e f u l l y u t i l i z e di n t h e c o m p o u n dm i c r o s c o p ei s d u e t o t h e l i m i t e d resolving power of the objective,which is determinedby the wavelengthof the light u s e d a n d t h e n u m e r i c a al p e r t u r e . However,sufficientlyhigh resolvingpower a n d a m a g n i f y i n gp o w e r h i g he n o u g h t om a k e the resolvedimage detail clearly visible still do not enablea compoundsystemto present the eye with an undistortedimage of this

10 detail. In addition,the errors inherentto a greateror lesserdegreein any imageformed by the lenses have to be eliminatedto such an extent that the overall system guarantees a largely unaberrated reproduction of resolved image detail. While-as we have seen-the resolving powerat a givenwavelengthof light depends exclusivelyon the objective,the image-forming properties are determined jointty by the objective and the eyepiece, although the primaryinfluenceis the type of objective. The magnifying power is determined on the one hand by the objectiveand the eyepiece,but on the other alsobythe mechanical system of the microscope connecting the two,becauseits Iengthdeterminesthe optical tube length. Since the demands made with regardto resolvingpower,magnifyingpower and image-forming properties cannot be satisfiedwith a singleobjectiveand eyepiece system, the connecting element, the body tube, must be designedso that the two componentscan be easilydetachedfrom it. This is why the lenselementsof both the objective and the eyepieceare accommodatedin special "mounts". The former have a standard threadby whichthey can be screwedinto the lower end of the body tube. The simpler, tubular mounts of the eyepiece lenses are slipped from above into the suitablyshaped eyepiecetube. Parfocalizationof objectivesand eyepieces

To facilitate the exchange of objectives, so-called "objective changers" are usually . inserted between the objective and the body tube. The location of the plane separaiing the body tube from the objectiveon the one hand and the eyepieceon the other is determined by practicalconsiderations: The tube should always be in the same positionin relationto the specimen. The image must remain in focus when

11

m : mechanicaltube length a : object-to-image distance b : object distanceof objective : intermediateimagedistance of eyepiece - working distanceof the objective

objectivesor eyepiecesare changed. ln microscope language,this is called "parfocalizationof objectivesand eyepieces". To satisfythe latter requirement,which is essentialfor undisturbedwork with the microscope,the optical tube length cannot be the same for all types of objectives.lt is the distancebetweenthe specimenand the aerial image that must be kept constant. With a given mechanicaltube length this can only be achievedby appropriatedesignof the objective mount. The length of this must be chosen so that the separationbetween the object plane and the undersideof the body tube againstwhich the objectiverests when it is screwed in is the same, and the lens systemis positionedso that the aerial image will always be formed in the same plane in the tube, regardlessof the objective focal length.The measureof the distancebetween objectiveplaneand objectivescrew flangeis the so-calledobject distanceof the objective. ln order that the image will remain in focus when the eyepiecesare exchanged, the eyepiecefocal plane must always coincide with the real aerialimage. In otherwords,the eyepiece flange must also be located at a fixed distance (intermediateimage distance of the eyepiece)from the plane of the aerial image in the tube, and the eyepiecemounts must be so designedthat their focal plane is alwaysat a fixed distancefrom their seating. Severalpoints have to be taken into account when fixing the three mechanical dimensions:ihe o b j e c td i s t a n c eo f t h e o b j e c tive,the mechanicaltube lengthand the intermediateimagedistanceof the eyepiece. The object distance of the objective is preferablychosen so that the objective of lowest power that is used frequentlyas well as objectivesof particulariylong construction can still be parfocalized.On the other hand, however,the objectivesmust not be made

12 excessivelylong or centeringwill become+oo difficult. A reasonablevalue has been found to be 45 mm, which we have been using for all our transmitted-light objectivessince1950. The intermediate image distance ol the eyepieceshould be chosenas short as possible to allow eyepiecesof short focal length also to be parfocalizedwithout difficulty. With our eyepiecesit is 10 mm. The mechanicaltube length should above all be chosenso that the microscopecan be dimensionedto suit its purposewithout bec o m i n gu n w i e l d yT. h e m e c h a n i c a l t u blee n g t h o f o u r m i c r o s c o p e iss 1 6 0m m . For the normal transmitted-lightmicroscope,the combinationof thesethree magnitudes results in a distance of 195 mm between the specimenand the aerial image. Object distance of objective

45 mm

mechanical tube length 1 6 0m m

intermediateimage planeof eyepiece

1 0m m

objectto-image distance 1 9 5m m

Once the tube length has been fixed, the total magnificationof the microscope only depends,in addition,on the focal lengthsof objectivesand eyepieces,i. e. the scale of the aerial image and the eyepiece magnification. Appropriateselection The user of the microscopewill find it of of inilial magnifications advantageif these two factors are chosen so of objectives and eyepieces that a Iarge number of total magnifications can be achievedwith a minimumequipment outlay. Such a series can be consideredas well coordinatedonly if it satisfiesthe followingconditions: The relationshipof every component in the serieswith the one precedingit and the o n e f o l l o w i n gi t s h o u l d b e o f e q u a l m a g n i tude. It should be possibleto obtainserieswith larger increments by leaving components with smallerincrementsout of a basicseries.

13 The values of the different components s h o u l d b e r o u n d f i g u r e so r s h o u l d a t l e a s t b e c l o s e e n o u g ht o r o u n d f i g u r e st o b e e x pressedby them with sufficientaccuracy. The seriesshould be so establishedthat once fixed for a power of ten it can be e x t e n d e da s d e s i r e d b y m u l t i p l y i n gb y 1 0 , 1 0 0 ,e t c . Theseconditionsare well satisfiedby the d e c i m a lg e o m e t r i cs e r i e so n w h i c h t h e G e r m a n l n d u s t r i a lS t a n d a r dD I N 3 2 3 i s b a s e d . T h e w o r k i n g g r o u p o n m i c r o s c o p yi n t h e standards committee of the German Prec i s i o nE n g i n e e r i n g a n d O p t i c a ll n d u s t r yh a s therefore proposed that the R 10 standard seriesfrom this standardbe adooted as the b a s i sf o r a m i c r o s c o p em a g n i f i c a t i o sne r i e s . It is containedin the draft standardon microscope magnifications,DIN 58,886,and is composedas follows: StandardSeries

10 100 1000

l.tc

t.o

12.5 125

to

160

1250

1600

20 200 2000

2.5 25 250

2500

3.2

32 320 3200

6.3

40 400 4000

50 500

o,J

630

80 800

etc.

When deciding on the characteristic values of objectivesand eyepieceson the b a s i s o f s u c h a s e r i e s ,t h e f o l l o w i n gp o i n t s mustbe takeninto consideration: There should be 4 to 5 main objectives with the aid of whichthe rangeof total magnifications requiredfor practicalwork can be c o v e r e ds, i n c eo n l yt h i s n u m b e ro f o b j e c t i v e s can be mountedon the conventionaltype of objectivechanger(revolvingnosepieces). T h e v a l u e sf o r t h e i n i t i a lm a g n i f i c a t i oonf the objectivesand eyepiecesmust also be taken from the aboveseries. Only then is the a d v a n t a go e f t h es t a n d a r ds e r i e sf u l l yu t i l i z e d , viz. that the product of any two figures is a g a i n a s t a n d a r df i g u r e .

14 In view of these considerationswe have chosen the following magnification incrementsfor our objectives. Only in rare cases and in the case of special-purpose objectives have important reasons prompted certain deviations. Series of initial magnifications of objectives Basic series Main series S i m p l i f i e ds e r i e s

2.5 4 2.5 2.5 (2.5\

Seriesof initial magnificationsof eyepieces

4 x 5 x 6 . 3 X8 X 1 0 x 1 2 . 5 x1 6 x 2 0 x 2 5 ) <

6.3 10

6.3 10 10

16 25 16

40 40

40 40

63

100

100 (100) 100

The numerical aperture chosen for the different objective magnificationsdepends largelyon the qualityof correction.In general, the largestapertureis used that is possible and justified under the circumstances. The numericalaperturesapplyingto our objectives may be taken from the different objectivetables. Field of view and viewing angle

In the compound microscope,the image is sharplylimitedby a diaphragmin the eyepiece which is called the eyepiecefield stop. Its diameterdependson the focal lengthand type of the eyepiece and is limited by the inside diameter of the tube accepting the eyepiece. This diaphragm allows only a certainportionof the real intermediateimage to be viewed. The diameter of this field is called the field-of-viewnumber. In the tables included in this booklet it is indicated for eachof the eyepieces.This numbermakes it possibleto determinethe diameterof the object portion which can be covered with the eyepiecefield of view. This so-called obiect field is determinedby dividing the field-ofview number by the initial magnificationof

15 the objective used-if necessarymaking alIowance for a factor due to body magnification or an intermediateoptical system. The field-of-viewnumber and the eyepiecefocal lengthalso serveto determinethe viewing angle under which the eye sees the entireimage. lf S is the field-of-viewnumber, then the viewing angle w results from the expression . t9

w 2

S z . f* ,

T h i sv i e w i n ga n g l ei s a l s o i n d i c a t e di n t h e differenteyepiecetables. All factors determining the magnifying power of the compound microscopeand its relationshipto the resolvingpower given by the apertureof the objective(rangeof useful magnification)can be representeddiagrammatically as is shown by the following example of a typical series of objectivesand eyepieces. The horizontal ines in the diagramrepresentthe steps by which the total magnification increases in accordance with the standard series, page 13. The solid lines from the lower right-handcornerto the upper left-handcorner are guide lines for the objectives, the magnification and numerical aperture of which are indicated beside the l o w e re n d o f t h e g u i d e l i n e . T h e g u i d e l i n e s for the eyepiecesare the dash-dottedones r u n n i n gf r o m t h e l o w e rl e f t - h a n dc o r n e r t ot h e upper right-hand corner. The eyepiece magnificationand the field-of-viewnumber a r e i n d i c a t e db e s i d e t h e i r l o w e r e n d . T h e guide lines for the eyepiecesintersectthose of the objectivesat the steps which indicate the total magnificationof the corresponding c o m b i n a t i o n .T h e c o l o r e d f r a m e l i m i t s t h e range of useful magnificationas defined by Abbe.

16 Correctionof aberrations

Accordingto the laws of geometricoptics, there is a considerable number of errors inherent in the image formed by an optical lens. Of these, the following affect image points even near the optical axis: sphericalaberration s i n ec o m a longitudinalchromaticaberration chromaticdifferenceof sphericalaberration. Towardsthe edge of the field,the following aberrationsare increasinglyevident: coma astigmatism curvatureof field distortion chromaticdifferenceof magnification. It is impossibleto correct all these aberrations at once and completely. They can only be more or less reduced, greater emphasisbeing placed on the reduction of some than othersdependingon the intended use of the opticalsystem. Thetechnicalmeansrequiredfor the satisfactory correction of optical aberrations dependprimarilyon the degreeof perfection d e s i r e d ; i n a d d i t i o n ,t h e y d e p e n d o n t h e desired numericalaperture.

Special attention must be paid to the effect which the cover glass generallyused in the microscope for examiningspecimensby transmittedlight h a so n i m a g eq u a l i t yT. h i s i n f l u e n c ei s c l e a r l y noticeablewith objectivesof largernumerical aperturethan 0.3 to 0.35. lt takes the form of sphericalovercorrectionand must be compensatedby an appropriateresidueof undercorrection in the objective if the latter is designedfor examiningcoveredspecimens. This is, of course, possibleonly if the overcorrection introducedby the cover glass is always identical,and this is only the case if the cover glass has a certain thicknessand refractiveindex,and the specimenis in very

tJl';""?"JTlffi; andirsimporrance

17 Vt,n 3200 2500 2000 1600 1250 1000 800 630 500 400 320 250 200 160 125 100 80 50 10 32 25 20 t6 12,5

18 close contactwith the undersideof the cover glass. Microscopeobjectivesare normallycorrectedfor a coverglassthicknessof.0.17mm. lf the cover glasses actually used deviate from this nominalthickness, they will produce a more or less disturbingover- or undercorrection,dependingon the numericalaperture of the objective employed. The following table indicatesthe amount of deviationfrom nominalthicknesswhich is tolerablewithout any noticeableloss of image quality. Cover-glassthickness with dry objectives N.A.of objective

Admissible deviation fromnominal thickness of 0.17mm

0.08- 0.3 0.3 - 0.45

0.45- 0.55 0.550.650.750.85-

0.65 0.75 0.85 0.95

+0.07 +0.05 + 0.03 + 0.02 +0.01 + 0.005

Table 2 Approxirnaterange of admissiblecover-glassthickness (mm)

-0.3 0 0.1 - 0.24 0.12 -0.22 0.14 -0.20 0.15 - 0.19 0.16 - 0.18 0 . 1 6 5- 0 . 1 7 5 This table shows that with objectivesof very high numerical aperture the optimum imagequality is achievedonly if specialcare is taken to use only cover glasses of prescribed thicknessand if the object detail on which the microscopeis focused is in direct contactwith the undersideof the coverglass. However, this will be the case only very seldom. Generally,there will be a more or lessthick layerof mountingmediumbetween the focusing plane and the undersideof the cover glass,which has about the same effect on the correction as if the thicknessof the cover glass were increased by the same "effective cover-glassthickamount. The ness" is therefore composed of the actual

19 cover-glass thicknessand the aforementioned l a y e ro f m o u n t i n gm e d i u mb e t w e e nt h e f o c u s i n g p l a n e a n d t h e u n d e r s i d eo f t h e c o v e r glassT . h e r e s u l t i n gi n a c c u r a c yh a sp r o m p t e d objective manufacturers to use special mountsfor all objectiveswith whichsuchfine d ifferencesmatter.Theseso-calIedcorrection collars allow one lens elementto be shifted so that the over- or undercorrectiondue to a deviation of the cover-glass thickness f r o m t h e n o m i n a vl a l u ec a n b e c o m o e n s a t e d . F o r t h i s p u r p o s e t, h e c o r r e c t i o nc o l l a r h a s a k n u r l e d r i n g w i i h a g r a d u a t i o na n d i n d e x . T h e f i g u r e so f t h e g r a d u a t i o (n1 2 . . . 1 7 . . . 2 2 1 indicate the cover-glassthickness in hundredths of a millimeter.Optimum image q u a l i t y i s o b t a i n e dw h e n t h e f i g u r e c o r r e s ponding to the thicknessof the cover glass used is oppositethe index. l n g e n e r a lm i c r o s c o p i cp r a c t i c ei t w i l l n o t be possibleto measurethe effectivecoverglassthicknessdirectly.lt is thereforenecessary to use indirectmethodsto determinethe correctsettingof the correctioncollar. 1. The only method which can be used in all circumstances and at the same time ensures the most accurate settinq of the correction collar, consists in measuring the effective cov-er-glass thickness with the aid of the microscooe: . . . U s i n g a 4 0 x , N . A . 0 . 6 5 ,4 0 X . N . A . 0 . 7 5o r 4 0 y , N . A . 0 . g So b jective, the condenser is stopped down to half the obiective 9perture.and the microscope successively focused on the surlace_ot tne cover gtass and the focusing plane with the aid of the fine adjustment. The corresponding readings of the fine adjustment are noted down. The difference be[ween the rwo settings gives the optical thickness of the cover qlass, which has t o b e c o n v e r t e d t o t h e m e c h a n i c a l l y " e f f e c t i v e t h i c : k n e s b "b v m u l t i plying it by a factor K. The latter'is preferably determinei once a n d . f o r a l l b y _m e a n s o f a n e x p e r j m e n t . F o a t h i s p u r p o s e , t h e thickness D, of a few ordinary cover glasses is acctiratblv determined by means of a. measuring-aid (micrometer, dial gage), whereupon thelr optical thjckness D, js measured with the mlcroscope as described above. The desired factor K results from the two measurements:

K=+

It is not, as one might assume, identical with the refractive index ol the cover olass. Example: K iJto be determined with two cover qlasses of diflerent thickness. Measurements show the followino thickn esses. Cover glass No. 1 N o . 2 ( n D= 1 . 5 2 8 8 ) Dl mm 0.161 0.240 D, mm 0.102 0.152 We thus obtain for DriD' = K 1.529 1.572

20 2 . W i t h l e s s , b u t s t i l l s u f f i c i e n ta c c u r a c yt h e e x p e r i e n c e d m i c r o s c o p i sw t i l l b e a b l e t o a d j u s tt h e c o r r e c t i o nc o l l a r b y t u r n i n g i t u n t i l a f i n e , d a r k o b j e c t d e t a i l i s i m a g e dw i t h o p t i m u m conIrasl.

It follows from the aforesaidthat objectives designedfor use with cover-glassspec i m e n s c a n n o t b e e m p l o y e df o r e x a m i n i n g uncovered specimens. For use with uncovered specimensspecially corrected obiectivesare available. I I I ustration : R a n a ,f r o g , b l o o d s m e a r . N E O F L U A R6, 3 x , 0 . 9 0N . A . , c o r r . Magnification 500x In the uppermicrograph t h e c o r r e c t i o nc o l l a r h a s b e e n a c c u r a t e l ys e t f o r c o v e r - g l a s st h i c k n e s s , i n t h e l o w e r t h e s e t t i n gd e v i a t e s b y 0 . 0 1m m f r o m t h e c o r r e c tv a l u e .

,&

w The immersionmethod

An extremelyefficientmeansof improving the image quality with objectives of high n u m e r i c aal p e r t u r ei s t h e p r i n c i p l eo f i m m e r s i o n . l t c o n s i s t si n u s i n ga l i q u i db e t w e e nt h e specimenand the front surfaceof the objective, which if possibleshould have the same optical propertiesas the glass of the front lens (homogeneousimmersion). In accorda n c ew i t h t h e f o r m u l a d -

N.A. n 'sino this will also increasethe resolvingpower by

21 the factor n, an advantagewhich today is f requentlyconsideredas the primarypurpose of immersion. Since an objectivecan be far better corrected for homogeneousimmersionthan a dry system of identicalfocal length and numericalaperture,it may also be of advantage to use the immersionmethodwith systemsof longer focal length. This gives objectives p e r m i t t i n ga h i g h e re m p t y m a g n i f i c a t i oann d thus makingit possibleto covera wide range of resultant magnificationsby simple exchange of eyepieces. Another advantageof the immersionmethod is that neither the cover-glasssurface nor the front lens of the objectivereflectany light so that for critical work the image is of c o n s i d e r a b l yh i g h e r c o n t r a s tt h a n w i t h a n otherwiseequivalentdry objective. Since the optical characteristicsof the immersionliquids have to be taken into account in the computationof the objectives, similar to those of the cover glass, it is essentialto use only the prescribedimmers i o n o i l . T h i s i s a l l t h e m o r e i m p o r t a nat s t h e p r i n c i p l eo f r i g o r o u sh o m o g e n e i t yh a s b e e n abandonedwith manyof the highlydeveloped immersionobjectivespresentlyin use. Insteadof the usual oil (refractiveindex n o [ 2 0 oC ] : 1 . 5 1 5 ) w , a t e r ( n o : 1 . 3 3 3 )o r glycerin (no : 1.455)are occasionallyused a s i m m e r s i o nm e d i a f o r s p e c i a l p u r p o s e s . Water immersionis used for examiningobjects in water. Glycerin is used if for some reasonthe objectivefront lens and the cover glass are made of amorphous quartz and approximatehomogeneityis desired. Objectives designed for homogeneous immersionmay be used with coveredor uncovered specimens. The cover-glassthickness is naturallyof no importancewith these systems. lt is differentwith present-dayimmersionobjectives,in which the principleof

22 homogeneityhas beenabandoned.This point should be rememberedif immersionobjectives computed for covered specimensare also employedfor viewingsmearswhich are left uncoveredto save trouble. This is normally the case in the examinationof blood and bacteria smears. While the slight degradation of the image thus produced may still be tolerablefor routinework, the trouble of covering the specimen should definitely n o t b e s h u n n e di n c r i t i c a w l o r k w h e r ef u l l u s e is made of the high performanceof the objective. lt is true that the lack of a coverglass can be made up by other means,such as the use of immersionoil of higher refractiveind e x - n o 2 0 o C : 1 . 5 2i n s t e a do f 1 . 5 1 5 - o rb y increasingthe tube length,but who wants to use two differenttypes of immersionoil and where can a microscopebe found today in whichthe tube lengthcan be increasedup to 25 mm! Finally,cbjectivesspeciallycorrected for uncoveredspecimens,as normally employed for reflected-lightwork, may also be used for this purpose.

ZEISSobjectives classificationof objectives

23

The different types of objectives are generallyclassifiedin accordancewith the degree to which their aberrationshave been corrected,their designationindicatingchromaticcorrectionfirst. This also automatically constitutesa classificationaccordingto the technicalmeans requiredfor achievingtheir respectivedegreesof correctionand hence their price categories. We distinguishbetweenthe followingcorrectioncategories: achromaticobjectives, semi-apochromaticobjectives, apochromaticobjectives. In their original form, all objectives in thesethree categoriesexhibitfield curvature which increasesconsiderablywith decreasing focal length. As long as they were primarily used for visual observation,this was not felt as a seriousdrawback,because any desired point in the field of view could easily be focusedwith the aid of the fine adjustment. However,since the techniquesof photomicrographyhave assumed such importance,new typesof objectiveshavehad to be developedin which the curvatureof the field is eliminatedto a sufficientdegree, in addition to the other aberrations.Years of computation were required to solve this extraordinarilydifficult problem in a satisfactory manner. In 1938 our firm introduced the first objectivesgiving a flat field, under the designationPlanachromats.ln the meantime, countless improvements have been made in these objectives. As a result of this untiring work, a state has now been reachedwhich permitsnot only achromatsbut also apochromatsto be made as flat-field objectives. Thus the aforementioned three categories of objectives are supplementedby those of the Planachromats and the Planapochromats.

24 Thesecan be suppliedboth as dry objectives and immersionobjectives. There are objectivescorrected for the observationof cover-glassspecimens and others for use with uncoveredspecimens.While the objectives corrected for covered specimens are mounted and parfocalizedso that they may be usedfor transmitted-light work, the objectives for uncoveredspecimensare-with few exceptions-designedfor use in conjunction w i t h v e r t i c a li l l u m i n a t o r s . To satisfythe special requirementswhich haveto be madefor observationby polarized light (strain-freecomponents,provisionfor accuratecenteringof objectives),objectives in centeringmountsare supplied,the optical componentsof which are manufacturedand mountedwith specialprecautionsto guarantee completefreedom from strain (POL objectives). In principle,practicallyall objectivescan be equippedwith phase platesfor use of the Zernike phase-contrastmethod. Our manufacturingprogram includesa wide choice of such objectives. Our opticaldesignersare today usingthe most advanced techniques and the latest glass types. They are constantlystrivingto find the best for the microscopeoptics we manufacture.the best that can be achieved with the meanspresentlyat our disposal.The use of highlyperfectedglasstypesmay,however, occasionally have the disadvantage that a greater sensitivityto acids and water vapor is unavoidable.lt is obviousthat this appliesaboveallto the most highlycorrected and therefore most expensivetypes of objective-if only in a few cases.Allowancefor this fact can be made by usingonlythe lesscostly objectivesfor work with acids. A lens error which has a very important influence on the satisfactoryimaging of a visualfield of a certainextensionis the chro-

25 matic differenceof magnification.Eversince Abbe'stime,this error has generallynot been correctedin the objectivebut by meansof an eyepiecehavingan error of identicalmagnitude but oppositedirection. Such eyepieces are called compensatingeyepieces. ln order that a singleseriesof eyepiecesmay be sufficient-a fact which is today consideredindispensablein the interestsof easyoperation of the microscopeby less experiencedpersonnel-all our objectives have the same lateral chromatic aberration. The fact that this is the casewith all our objectivesensures that the user of our microscopesneed not bother about which type of eyepieceto use for a certainobjective.Any of our eyepieces will do. However,our objectivesshouldnever be combinedwith eyepiecesof anothermake if a more or lessseriousloss of imagequality is to be avoided. The differentcategoriesof objectivesare : d istinguishedby thefolIowingcharacteristics Achromats

Achromatsare lenscombinationsin which, to keep the price down, only the back focal distancesfor the colors blue and red of the spectrumhave been made equal. This gives the mostfavorablecorrectionfor the brightest regionof the spectrum.ln this region,spherical aberration and sine coma as well as astigmatismhave,of course,been eliminated as far as necessaryor feasiblewith the means available at this price level. The residual chromaticaberrationin this type of objective c a n b e s e e n u n d e r o b l i q u e i l l u m i n a t i o na s violet and yellowish-green color f ringes around dark object details. Under straight i l l u m i n a t i o na n d w i t h t h e s p e c i m e no u t o f focus, it appearsas a weak violet cast above the plane of sharp focus and as a weak yellowish-greencast below that plane. These secondary colors are all the more pronounced, the better the other aberrations

26 have been corrected. Altogether,however, they are generallynot bad enoughto disturb visualobservation. The focal lengths of achromaticobjectives are chosen so that the upper limit of usefulmagnification can be reachedwith eyepiecesof relativelylow power. Eyepiecesof h i g h e r m a g n i f i c a t i o nt h a n 1 2 . 5 x s h o u l d thereforenot be used,or only in exceptional cases,e. g. for measuringand counting. Achromaticobjectivesare employed for routine work, for equippingteaching microscopesand for all applicationsin which critical observationis not required. lf due allowance is made for their characteristics, these objectivesmay also be usedfor photomicrography,even for color photography.We now only manufactureachromatsin simplemounts and exclusivelyfor transmittedlight. Planachromats

Planachromatsare objectivesof improved chromaticcorrection.in which the curvature of field has been eliminatedpracticallyentirely even for the largest field of view encounteredin the microscope.This,of course, requiresa much greateroutlaywhich results i n a c o r r e s p o n d i n g lhyi g h e rp r i c e . D u et o t h e importance of field flattening for viewing polished specimens under vertical illumination,almost all our objectivesfor this type of work are Planachromats.They are then called EPIPLANobjectivesand should be used togetherwith Kpl eyepieces. For reflecied-lightmicroscopywe have 1 . E P I P L A No b j e c t i v e sf o r b r i g h t - f i e l di l l u m i n a t i o n ,b y w h i c h t h e i l l u m i n a t i n gl i g h t i s transmittedto the specimenvia a reflecting means(planeglassor prism)throughthe objective. The objective acts as its own condenser. 2. EPIPLAN HD objectives for bright{ield a n d d a r k - f i e l di l l u m i n a t i o n B . r i g h t - f i e l di l l u minationis attainedas describedabove. In

27 d a r k - f i e l di l l u m i n a t i otnh e t i g h ti s g u i d e dp a s t the objective and concentratedin the specimen plane by meansof concentricmirrors or concentriclens systems. The concentric mirrors or lens systems are combined with the objectiveto form one unit. NEOFLUARS

Using fluoriteinsteadof crown glass,microscope objectivescan be built which are distinguishedby considerablyimprovedcorrectionof aberrationsalthoughthey havethe same number of lens elements as achromatic objectives.The design we use for our "NEOFLUARS" and which can be traced back to R. Winkel comes very close to the correctionof apochromaticobjectives.Only secondary color has not been completely eliminatedalthough it is far less noticeable than with the achromats.lt is obviousthat the I i m i t e dn u m b e ro f l e n s e l e m e n t su s e d i n t h e NEOFLUARSdoes not allow a correctionfor field curvature.However,the low number of glass-to-air surfaces in these objectives ensuresa minimumof flare so that they produce images of surprisinglyhigh contrast. The excellent correction of NEOFLUARS makes it possible to achieve considerably higher numerical apertures than in achromatic objectives.Thusthe N.A.of NEOFLUAR objectives-insofar as they are dry systemsis 15 to 30 o/oabove that of normal achromats of identicat focat tength (tabtes 8-10). NEOFLUARSmay therefore be combined

y,'*#'*":","#",{J'fi5:?i larly well suitedfor phase-contrast work. Planapochromats

With the aid of special glass types, which were then new, and fluorite,Abbe was the first to succeed, in the eighteen-eighties, in computing objectives of equal back focal distancefor more than two colors and, at the same time, far-reachingcorrection of the

28 other aberrationsas well. Abbe announced this new type of objective,which he called apochromat,on July 7, 1886. Ever since, it has been continuallyimprovedand today it is so highly developedthat further improvement appearshardlypossible,all the more so as it now gives a perfectlyflat field without sacrificing any of its other characteristics. Since this has become possible we only whichwe manufactureflat-fieldapochromats, "Planapochromats".Owing to the apocall chromatic correction of these objectives' residualchromaticaberrationcan no longer be recognizedin the image. lt is, of course, necessaryto use suitable eyepieceswhich compensatefor the chromaticdifferenceof magnification. The numericalaperture of our Planapochromats has been increasedto a few per cent abovethat of the NEOFLUARobjectives. They thus representthe ultimatein performance that is possible today-and probably that is possibleat all. As a result,these objectivesare usedwhenevermaximumresolution is requiredfor extremelycritical work. It is obviousthat they are superiorto all other typesof objectivein color photomicrography. Planapochromatsshould always be combined with Kpl eyePieces. ULTRAFLUARS

of ULTRAFLUARS Transmission

ULTRAFLUARSare special-purposeobjectivesdesignedso that the ultravioleilight is also usedfor imageformationin the microscope. They must therefore contain only material the transmissionof which is sufficientfor the desiredrangef rom 400 m,adown to about2O0mp^Glasscannotbe usedforthis purpose.Only amorphousquartzand fluorite are suitable.Since for manyyears it seemed impossibleto achievechromaticcorrectionevenjust for a small regionof the spectrumwith the aid of thesetwo materialsalone,so"Monochromats"were at first introcalled

29 duced, which were corrected for only one wavelength.Only recently have our optical designersaccomplishedthe feat of computing a series of objectivesof excellentchromatic correctionover the very large spectral regionfrom 230 m4 to 700 m4. Sincethen we have been making only one series of objectivesfor ultravioletmicroscopy.We call them ULTRAFLUARS. We do not manufactureany monochromatsor even reflectingobjectives, because these offer no advantages over ULTRAFLUARS,but only have disadvantages. Objective mounts

F i our e : C r - o s s - s e c t i odnl a g r a mo f P l a n a p o c h r o m a1t0, 0 x , 1 . 3 N . A . ,o i l , w i t h o b j e c ta n d f r o n t l e n s p r o t e c t i o n .

T r a n s i l l u m i n a t i o no b j e c t i v e s h a v e t h e standard W 0.8"X1/zd"thread for screwing into the revolvingnosepieceor single nosepiece. The high-powersystems,which may touch the cover glass, are equipped with resilientmountswhich give way if they knock a g a i n s tt h e s p e c i m e n .T h i s g u a r a n t e e sa d e quate protectionof both the specimen and the objective front lens. The mount of the immersionobjectives-exceptthe achromats -can be locked in retracted position so as to facilitateapplicationof the immersion liquid. In view of the Iarge number of objectives with differentcharacteristics which we manufactureit has beenfound convenientto make them differexternallyas well,so that the user will recognizeaI a glance what type of objective he has before him. They are theref o r e i d e n t i f i e db y t h e c o l o r a n d f i n i s h o f t h e mount,as well as its engraving(seetable 3).

30 Objectivemounts

Objective type

Planachromats NEOFLUARS Planapochromats ULTRAFLUARS

Table3

Upperpartof mount belt-polishe6 black chromium-plated, belt-polished chromium-plated, glossy

C h r o m i u m - p l a t e dC o l o r lowerpart of en-

Engraved

black

glossy

white

P l a n .E P I P L A N

belt-polished

black

NEOFLUAR

glossy

white black

Planapo ULTRAFLUAR

lmmersion systems are distinguished from dry objectivesby a blackor coloredring at the lowerend of the mount. In addition,the immersionmedium indicatedby the color of the ring is also identifiedby an abbreviation afterthe objectivedata. The followingcolors and abbreviateddesignaiionsare used on immersionobjectives:

lmmersionobjectives Table4 lmmersion Color medium of ring black oil Water white Glycerin orange Methylene iodide yellow

Designation Oel W Glyz Methylenjodid

Apart from the trade mark,our objectives are engravedf irstof alI with a f igure indicating the scaleat whichthe realintermediate image is reproducedatthe object-to-image distance fixed for our microscopes,i. e. the initial magnification(e. g. 25),then-after a strokethe value of the numericalaperture(e. g. 45). Below these two figures there may be additional data indicatingthe mechanicaltube lengthor the cover-glassthicknessfor which

31 the objectivesare corrected,as well as the s e r i a ln u m b e r . T h e m e c h a n i c atlu b e l e n g t hi n a l l o u r m i croscopesis 160mm. On objectivessensitive to deviationsfrom the prescribedcover-glass thickness, the cover-glassthicknessfor which they are correctedfollowsthe figure160after a stroke. lndicationsreferringto cover-glassthickn e s sh a v et h e f o l l o w i n gm e a n i n g : "0.17" the objective is sensitiveto deviations from a cover-glassthicknessof 0 . 1 7m m . the objective may be used with or without cover glass. "0" the objective should only be used without a cover glass. Specialobjectives,e. g. those containing strain-freelenses for polarized-lightmicroscopy, phase-contrastobjectives,etc., are identifiedby the abbreviationslisted in the f o l l o w i n gt a b l e : T a b l e5 Abbreviation

Meaning correctedfor use with uncoveredspecimens Phase-contrastobjectives

Phl Ph 2 (red) Ph3 Pol (red)

HD Epi

U s ea n n u l adr i a p h r a g m 1 I U s ea n n u l adr i a p h r a g m 2 | U s ea n n u l adr i a p h r a g m 3 J

of phase-contrast condenser

Objectivefor polarized-lightmicroscopy Objectivefor reflected-light work using bright-fieldor dark{ield illumination Objectivefor reflected-light microscopy Since the engravingon the objectivesis often in a positionwhere it cannot be seen once these have been screwed into the microscope,our objectiveshave colored rings at the lower end of the funnel, which are v i s i b l ei n a n y p o s i t i o na n d i n d i c a t et h e i n i t i a l

32 magnificationof the objective. This color code,which is independentof the type of objective,is explainedin the followingtable. Table 6

Color code for initial magnification lnitial magnification Color of ring

1 X

2.5X

4X

6.3x

8i10x 16x

25X

40x

63x

80/100x

o r a n ge

.. v- e l l o w

dark green

briqht

dark .,

wnlte

brioht green

DIUE

OIUE

In the compound microscope,the object ZEISSobjectivesfor photomicrography LUMINARS fields that can be recorded photomicrographically for low-powerwork are of limited size, in the case of our instrumentsa maxim u m7 . . . 8 m m . T h i s i s d u e t o t h e f a c t t h a t i t is possible neither to achievea sufficiently small scale of reproductionin a compound microscope,nor to magnifythe portionof the aerialimagecoveredby the eyepiecebeyond the limit imposed by the clear diameter of the tube. lf larger object fields are to be photographedat small scalesand with a flat field,we may only use a singlemagnification stage,i. e. an imageof the specimenmust be emulsion formed directlyon a light-sensitive by means of an objective of suitable focal length.Wherehigh imagequalityis required, specially developed systems are used the design of which is similar to that of photographic lenses. ln addition,it is advisableto employ a camera of variableextension. To cover a wide rangeof imagescales,we need "photomicrographicobjeca series of such tives" with carefullyselectedfocal-lengthincrements. These incrementsdepend on the degreeto whichthe cameraextensioncan be varied. Of course the extension is always limited. We manufacturesuch photomicrographic objectivesunderthe designaiionLUMINARS.

33 Accessories are available which allow these objectives to be used on our large cameramicroscopeULTRAPHOT, which can be equippedfor any type of microscopicand photomicrographicwork, as well as on our PHOTOMICROSCOPE and the UNIVERSAL researchmicroscope.For furtherdetails,see the operating instructionsfor these instruments. LUMINARSare always used without eyepieces. The shorterfocal lengths(16,25 and 40 mm) may occasionallyalso be combined with eyepiecesand used like ordinarymicroscope objectives.In this case,however,eyepieces must be chosen to match the correction of the LUMINARS.Suitabletypesare the eyepiecesof our stereomicroscopes and Ctype eyepieces.

ZEISSeyepieces Types of eyepiece

34

As was mentioned in the introduction (pageB),the eyepieceis designedto present to the eye the object detail resolvedby the objective and contained in the real interm e d i a t ei m a g eu n d e r a v i e w i n ga n g l ew h i c h is sufficientlylargefor easy recognition.This alone could be achievedwith a simple converging lens, but no influence could be exerted on aberrations. lf this is desired, such single-elementeyepieceswill have to be replacedby more complexsystems. In practice,however,these can be made only with relativelyshort focal Iengths,because on the one hand their diameter increasessharplywith growing foeal length, while on the other the exit pupil of the microscope-i. e. the image of the objectiveaperture formed by the eyepiece,which represents the plane where the observer'seye pupil must be located-is movedto an inconvenientlylong distance away from the eyepiece lens. Both these drawbacksare eliminatedby constructingthe eyepiecesf rom two more or less widely spaced components. one of which is locatednear the aerialimage. Here it affects primarilythe imaging of the p u p i l , w h i l e t h e s e c o n d c o m p o n e n tt a k e s over the eyepiecefunction proper, viz. that of magnifying.The first componentis called t h e " c o l l e c t i v eo r f i e l d l e n s " ,t h e s e c o n dt h e "eye lens". The field lens may be located before, in or behind the real intermediate image. lf it lies before the aerial image, it will reducethe latterby a certaindegreeand shift it towards the objective. Eyepiecesof this type are called Huygenianeyepieces.lf the field lens is locatedbehindthe real intermediate image,then, of course, it does not modify the latter. This is particularlyfavorwith the able for the purposeof measurement aid of micrometerdisks arrangedin the image plane. Eyepieces of this type are called Ramsdeneyepieces.

35 Huygenianeyepiecesresult in a shorter overall length of the microscopethan eyepiecesof the Ramsdentype. With short focal lengths,however,the latter type allows the exit pupil to be locatedfurtheraway from the eye lens. This is why eyepiecesof long focal length are usuallydesignedon the Huygens principle,those of short focal length on the Ramsden principle. The two components c o n s i s to f s i n g l ee l e m e n t so n l y i n t h e s i m p l e s t types of eyepiece. Severalelementsare invariably required per component if any influenceis to be exertedon the aberrationsof the eyepiece itself or the residualerrors in the imageproducedby the objective.Thus it has beengeneralpracticeeversincethe time of Abbe to compensatefor a rathertroublesome error frequentlyexhibited by the objective image and difficult as well as costly to correct in the objective-the chromatic difference of magnification-by using eyepieces which exhibit the same but opposite aberration.In addition,attemptshaveoccasionally been made to reduce field curvature by means of the eyepiece. Eyepiecescompensatingfor lateralchromaticaberrationare known as compensatingeyepieces. To facilitatethe use of our microscopes, we have computedall our objectivesso that the chromaticdifferenceof magnificationin the real intermediateimage they produce is alwaysthe same. We can thereforebe content to supplycompensatingeyepieceswhich make up for this degree of lateralchromatic aberration. This matchingof objective and eyepiececorrection,introducedin the interests of our customers,is ihe reasonwhy we have to warn our customersagainst using eyepiecesof other manufacturewith our objectives. The eyepiecesfor our stereomicroscopes, however,are not designed on the principle explainedabove. They have no compensat-

36 the ing effeci,becausein stereomicroscopes optical systems of the first magnification stage are also free from lateral chromatic aberration.Theseeyepiecesthereforecannot be combinedwith the usual microscopeobjectives. Intermediate systems changing the magnification

During practical use of the microscope, a change of magnification by means of changingeyepiecesis frequentlyconsidered inconvenientand troublesome,becauseihe eyepiecesnot being used at the momentare detached parts which may get lost or damaged. To counter this disadvantage' systems have been magnification-changing insertedbetweenthe objectiveand the eyepiece of the microscope.These may either be designedfor a stepwisechangeof magnification-whichwould correspondto a change of eyepieces-or as continuously variable systems. ln the latter, however, a more or less noticeableloss of image quality is unavoidable. We have therefore adopted the system of changing the magnification by steps. lf only two alternativemagnificationsare required-whichis generallyconsideredsufficient for teaching and laboratory microscopes used for routinework, for instancethen the magnificationchanger may be used. This is a two-componentsystemmountedso that it can be insertedinto the limb top of our STANDARDmicroscopes(STANDARDK' R o r W L ) . F o r t h i s p u r p o s et h e l i m b t o p i s equippedwith a spindlewhichcan be rotated through 90o and on which the magnification changer is secured by means of a coaxial screw. This arrangementoffers the advantage that the magnificationchanger is normally firmly attachedto the microscope,but can be removedif necessarY. The followingmagnificationchangersare available:

37 (see 0.8x;1x, 1x:1.6x, 1xZ2x Section on field-of-viewnumber and size of o b j e c tf i e l d ) . W h e n t h e m a g n i f i c a t i o cnh a n g e ri s s e t i n t h e p r o p e r p o s i t i o n ,t h e t o t a l m a g n i f i c a t i o n c o m p u t e df r o m t h e i n i t i a l m a g n i f i c a t i o nos f objective and eyepiece will be changed by the correspondingfactor. l f a r a p i dc h a n g eo f m a g n i f i c a t i oinn m o r e than two steps is desired,it is necessaryto employ a more complicatedoptical system such as that contained in our OPTOVAR. H e r e t h e a e r i a l i m a g e p r o d u c e db y t h e o b jective is first shiftedto infinityby means of a lower Telan lens of negativepower. This image is then viewed through a telescope system mounted above it. In the present case, the telescope system consists of an upper Telan lens of positivepower mounted at the lowerend of the tube and representing the telescopeobjective,and the usual microscope eyepiece. The two Telan lenses are h e l d b y t h e u p p e ra n d l o w e rw a l l so f a c y l i n d r i c a lh o u s i n g .T h e l a t t e ri s d e s i g n e ds o t h a t small Galileantelescopescan be insertedin the space betweenthe two Telan lenses.For t h i s p u r p o s e t, h e t e l e s c o p e sa r e m o u n t e do n a revolvingdisk which can be controlledfrom the outside. The magnifyingfactors to be l iththe magnification a c h i e v e da r e i d e n t i c aw of the telescope systems. Apart from the factor 1, which is effectiveif no telescopeis in the light path,the OPTOVARcan be set for 1 . 2 5 x ,1 . 6x a n d 2 X o r 0 . 8x , 1 . 2 5 xa n d 1 . 6x magnificationwith the aid of telescopes.In addition,anothersystemcan be moved into the light path, which has the effect of a Bertrand lens and permits the exit pupil of the objectiveto be viewed,for instancefor observing interferencepatterns,for centeri n g t h e a n n u l a rd i a p h r a g mi n r e l a t i o nt o t h e p h a s e p l a t e a n n u l u si n p h a s e w o r k , o r f o r checkingthe stoppingdown of the objective.

38 This image-formingsystem for pupil observationmay also be used to advantagefor p r o d u c i n ga n o n l y s l i g h t l ym a g n i f i e di m a g e of the specimen,if it is desired to scan the specimenfor generalorientation.ln this case its magnificaiionfactor is approx.1.25. sysIntermediatemagnification-changing page 88. in table 36 on tems are listed Field-of-viewnumber and size of object field

Magnification-changing systems are a convenientmeans of varying the size of the object field covered for a certain field-ofview number of the eyepiecewithout changing any mechanicaldimensionsof the microscope. lf the scale of the real intermediate imageis increasedby meansof suchan intermediatesystem,a smallerobject field will be covered. On the other hand, if the scale of the real intermediateimage is reduced,the objeci field will, of course, be larger' The latter is undoubtedly an advantage in all cases where many specimens have to be scanned.The only drawbackis that the total magnificationis reduced by the same factor by which the scale of the intermediateimage is changed. This disadvantage,though, can easily be offset by a higher-powereyepiece which should,however,have the same fieldof-viewnumberas the one originallyused. An example may serve to illustratethis: C o m b i n i n ga 1 0 x o b j e c t i v ea n d a 1 0 x eyepiecewith a field-of-viewnumber of 16, a n o b j e c tf i e l d S o f 1 6 : 1 0 : 1 . 6 m m w i l l b e coveredunder a total magnificationof 100X ' Insertingan intermediatesystem with a factor of 0.8 will increasethe object field by -the reciprocalfactor,since we have 16 16 =10.0€: B:zmm' lf we wish the total magnificationto remain unchanged,insteadof the 10x eyepiecewe

39 shallhaveto usean eyepiec" = 12.5x ffi w h i c ha l s o h a s a f i e l d - o f - v i e w n u m b e ro f 1 6 . F u r t h e rm a g n i f i c a t i o no f t h e o b j e c t f i e l d i s possibleif eyepieceswith increasedfield-ofview numbers, so-called wide-angle eyep i e c e s ,a r e e m p l o y e d .S u b s t i t u t i n g1 0 X o r 12.5x wide-angleeyepieceswith a field-ofv i e w n u m b e ro 1 2 0f o r t h e o r d i n a r ye y e p i e c e s , the aboveexamplecan be writtenas follows: Withoutintermediatesvstem 20 S=*:2 mm. IU

With 0.8X intermediatesvstem

20 "-10'0.8-

:2.5 mm.

I n o t h e r w o r d s ,t h e s a m e o b j e c t f i e l d i s c o v e r e du n d e r1 0 0 X t o t a l m a g n i f i c a t i oans i f a 1 0 X e y e p i e c ew i t h a f i e l d - o f - v i e w number of 25 were used. Wide-angle eyepieces have been developed for the observationof larger fieldsof-view. The following table lists the eyepieces and their field-of-viewnumbers. The * i m a g ed i a m e t e rg i v e n i n t h e t h i r d c o l u m ni s basedon the conventionalobject distanceof 250 mm. lt is the product of the field-of-view n u m b e ra n d t h e e y e p i e c em a g n i f i c a t i o n . T a b l e7 Kpl Wide-angle yepiece

Field-of-view number

l m a g ed i a m e t e r *

to

250 mm 256 mm

12.5x 16X

Mountsand identificationof eyepieces

As is usual, the lenses of the eyepiece systems are housed in relatively simple m o u n t sT . h e s ei n t u r n a r e c o n t a i n e di n a t u b e fitting into the upper end of the microscope lube with the eye lens at the top and the field

40 lensat the bottom. The mountof the eye lens is designedso that its projectingedge may be gripped. The field lens is either located right in the eyepiecetube or likewise contained in a special mounting ring. The eyep i e c e t u b e o r m o u n t i n gr i n g h a s a f e m a l e thread of M 22X 0.5 into which light filters or other accessoriesmay be screwed, as required. The outsidediameterof the eyepiecesis standardized. This standard diameter is traditional in the normal microscope. lt is a stand23.2mm. In our stereomicroscopes ard diameterof 30 mm has been adopted. ln addition,the diameterof the eye-lensmount of all our eyepiecesconformsto the German DIN Standard 58,881to facilitate the attachthe eyement of accessories.Consequently, is eyepieces all our lens mount diameterof 28 mm. As is the general practice today, the magnificationof the eyepiecesis indicated " ". Lettersbefore by a figure followed by x the magnificationmark the type of eyepiece. Since we manufactureonly compensating eyepieces,such an identificationwould normally be superfluous. However, our eyepieces of higher power are so designedthat they producea flat field,which is not necessary for the low-power systems. The latter are thereforemarked C (compensatingeyepieces)to distinguishthem from the former marked Kpl (compensatingf lat-field eyepieces). The fact that the eyepiecesare used to view a real image may be utilizedto make a sharp image of a reticule, graduation and otherfiguresor pointersvisibletogetherwith this object image. These figures are engraved on glass plates (micrometerdisks) which are insertedin the diaphragmplane of the eyepieces. However,since they will not necessarilybe seen sharplywith normaleye-

41 pieces,above all if the eye of the observer is not free from visual defects,eyepieceswith a focusingeye lens are used for this purpose. In addition,theseeyepiecesare designedso that the micrometerdisk can be easily,inserted and will be centered once it is in position. The micrometer disks normally suppliedby us are Iistedon page 75. For polarized-lightmicroscopy the crosshairs marking the center of rotation of the stage must be very accurately centered. Since this cannot be achieved by the mere insertionof crosshairdisks,we manufacture special eyepieces with accurately adjusted crosshairsor crosshairmicrometerdisks for this purpose. For critical work, partly for very special measuring or counting problems, we also manufacture a great variety of specialpurpose eyepieceswhich are listed after the ordinary eyepieces.

ZEISScondensers

42

ln microscopyself-luminousobjects are rarelyencountered,in fact only in fluorescent work. In general,the objectsto be examined u n d e r t h e m i c r o s c o p em u s t b e s u i t a b l yi l l u minatedto allow their details to be imaged and viewed. Either incident or transmitted l i g h tm a y b e u s e df o r i l l u m i n a t i o na,n d i n b o t h cases either the bright-fieldor the dark{ield method may be employed. In the former,an imageof the light source is formed in the objectiveaperture,while in the latterthis is not the case. W i t h a p e r f e c tb r i g h t - f i e l di l l u m i n a t otrh e aforementionedsource image should fill the objectiveaperturecompletely,becauseonly then can the full apertureof the objectivebe utilized,if necessary.In addition,the object field reproducedshould,of course,be comp l e t e l ya n d e v e n l yi l l u m i n a t e d . When using high-apertureobjectives,a source image of sufficient size can be achievedonly with very large light sources. However,since the size of the light sources generally used today is limited, it must be magnified by optical means. This is done with the aid of a lens systemlocatednear the specimen,the so-calledcondenser. The light sourceto be magnifiedmust be brought as close to the focal plane of ihe condenseras possibleso that its magnified image will be produced at a sufficientdistance from ihe specimen. Otherwise the a n g l eo f i n c i d e n c eo f t h e p e n c i l so f r a y s i l l u minatingthe object pointswill vary greatlyin the centerand the outerfield,thus producing i n c r e a s i n g loyb l i q u ei l l u m i n a t i o ino w a r d st h e edge of the image so that the image character will no longer be homogeneous.Since it is not normallypossibleto locatea light source in the condenserfocal plane due to the heat it generates,the source is arranged at an appropriatedistance from the microscope and a source imagefillingthe con-

43 denser aperture is formed in the condenser focal plane with the aid of another lens system,the lamp condenser.This offersthe followingadditionaladvantages : The effectivearea of this image can be r e d u c e db y m e a n so f a n i r i sd i a p h r a g mw, h i c h i s a c o n v e n i e nm t e a n so f c o n t r o l l i n gt h e i l l u minating aperture. Such an aperture iris is practically always permanentlyattachedto the condenser. It is easy to achievea very homogeneous i i l u m i n a t i o no f t h e o b j e c t f i e l d r e p r o d u c e d by adjustingthe condenserso that it forms a s h a r pi m a g eo f t h e h o m o g e n e o uisl l u m i n a t e d apertureof the lamp condenseron the spec i m e n . A n i r i s d i a p h r a g mi n t h i s p l a n e( l a m p field stop) makesit possibleto matchthe size o f t h e i l l u m i n a t e df i e l d w i t h t h a t o f t h e f i e l d imaged (Kiihler's method of illumination). In accordancewith these generalobserv a t i o n sa , condenseh r a s t w o f u n c t i o n si n a n e c o n o m i cb r i g h t - f i e l di l l u m i n a t i n sg e t u p : 1 . T h e c o n d e n s e rm u s t b e c a p a b l eo f p r o d u c i n gc o n e so f r a y sf o r i l l u m i n a t i n tgh e o b ject points,the axes (principalrays)of which shouldas far as possiblebe paralleland perp e n d i c u l atro t h e s p e c i m e np l a n ea n d w h o s e aperturecan in certain cases be as large as the apertureof the objectiveemployed. 2 . T h e c o n d e n s e sr h o u l df o r m a h i g h - q u a l i t y i m a g eo f t h e l a m pf i e l d s t o p i n t h e s p e c i m e n plane. To satisfythe first condition,a universally applicablecondenserwould haveto havethe h i g h e s t n u m e r i c a la p e r t u r eo c c u r r i n g w i t h the objectivesused (1.3-1.4). However,such a high illuminating a p e r t u r ei s a c t u a l l yu s e d only in rare casesin microscopicpractice. In fact,to increaseimagecontrastthe illuminati n g a p e r t u r es h o u l db e s m a l l e rt h a n t h e o b jective aperture. Experiencehas shown that even in the caseof immersionobjectiveswith t h e e x t r e m e l yh i g h a p e r t u r eo f N . A . ! 1 . 4 a n

44 i l l u m i n a t i n ga p e r t u r e o f l e s s t h a n 1 . 0 i s generallysufficientso that an N.A. 0.9 condenserwill do in the great rnajorityof cases' This offersthe followingadvantages: The correctionof the condensercan be improvedwithout increasingits cost. The focal length and obiect distance of the condensercan be increased. As a result,the condenserdiaphragmcan more easily be arranged in the correct position,in the focal plane. The front lens need not be connectedto the specimenslide by m e a n so f a n i m m e r s i o nl i q u i d . For reasons of price, condensers are generallycorrectedonly as far as is possible at minimumexpense. Especiallywhen used with higherapertures,it is thereforevery difficult to achievea satisfactoryimage of the lamp field stop with most condensersdue to their sphericaland chromaticaberrations'In o r d e rt o o b t a i na h o m o g e n e o u s li yl l u m i n a t e d object field the lamp field stop must be opened further than would normally be necessary.However,this is of no importance as long as imagecontrastis not impaired. For critical work and in conjunctionwith objectiveswe recommend high-performance that correctedcondensersbe used,whichare available in the form of achromatic-aplanatic condensers. With a lamp field stop of given diameter, a condenser of a certain focal length will only illuminatean object field of a certain size. lt is impossibleto design condensers suited for illuminatingall the aperturesand fields of view used in practice. This can be achievedonly if-as with the objectives-condensers of different focal length are employed. Many condensersare thereforedesigned so that a relativelyshort-focuscondensercan be convertedinto a condenserof longerfocal lengthand lower maximumaperture by removing its front lens or a front

45 component. F o r t h i s p u r p o s et h e f r o n t l e n s i s e i t h e r unscrewedor, where this is technicallyfeasible, swung out of the light path. All condensers are provided with the mechanicalfittings required for their use. The extentand design of these are indicated i n t h e f o l l o w i n gt a b l e s . The type of mount used to attachthe condenser to the microscope depends on the t y p e o f i l l u m i n a t oer m p l o y e d . l f t h e l i g h t o f a s e p a r a t ei l l u m i n a t o ri s reflectedinto the condenserby means of a m i r r o ro r i f a n i n t e g r a li l l u m i n a t ow r ith a suff i c i e n t l yl a r g e r a d i a n tf i e l d i s a v a i l a b l e( e . g . low-voltagebase iliuminatoror on-baseilluminator),the condenserneed not be centerable. W i t ho u r m i c r o s c o p e st h, e s i m p l e sdt e s i g n consists of a condenser sleeve mounted underneaththe microscopestage,into which the condenseris inserted. When the condensermust be movablein the axial direction,however,it is mountedon a rack-and-pinion condensercarrier. I n a l l o u r l a r g em i c r o s c o p e (sS T A N D A R D , W L , U N I V E R S A LP, H O T O M I C R O S C O Pa E nd ULTRAPHOT) the low-voltage illuminator normallyused as light source is permanently attached to the microscope. T o a l l o w t h e a f o r e m e n t i o n eidl l u m i n a t i n g techniquesto be employedwith sufficientaccuracy, a device had to be incorporatedin t h e i l l u m i n a t i n sg y s t e mw i t h t h e a i d o f w h i c h t h e i m a g eo f t h e l a m pf i e l ds t o pf o r m e di n t h e specimenplanecould be centeredin relation to the field reproducedby the microscope. We thus providedfor a displacementof the condenserby meansof two centeringscrews on the condensercarrier,which act against the force of a spring. This devicealso serves to hold the condenserwhich is insertedinto it with a heat-treateddovetailring. The con-

46 denser can here in any case be axially displaced with the aid of the condenser carrier to allow the image of the lamp field stop to be focused in the specimenplane. Z-type condensersare used with the condensercarriers. Dark-fieldillumination

i s u s e d ,t h e l i g h t l f d a r k - f i e l di l l u m i n a t i o n from the condenserdoes not enter the objective directly. Only the light diffractedby t h e s p e c i m e n( i n t h e c a s e o f i n c i d e n ti l l u mination,the light reflectedby the specimen) entersthe objectiveand formsthe image. As a result,the areas in the field of view which containno object structuresremaindark. W i t h d a r k - f i e l di l l u m i n a t i o nt h, e s p e c i m e n i s a c t u a l l yi l l u m i n a t e db y a h o l l o w c o n e o f l i g h t , t h e l o w e s t a p e r t u r e ( i n t e r i o rl i m i t o f aperture)of which is larger than the numerical apertureof the viewingobjective. D a r k - f i e l di l l u m i n a t i o nr e q u i r e sp o w e r f u l l i g h t s o u r c e s a n d s p e c i a l c o n d e n s e r s .l m mersionobjectivesof highernumericalapert u r e t h a n1 m u s tb e e q u i p p e dw i t h a n i r i s d i a phragmto allowtheir apertureto be reduced. W i t h f u l l y o p e n i r i s d i a p h r a g mt h e s e o b j e c tivesare employedfor brig ht-fieldi ||um ination. objectivesare unsuitablefor Phase-contrast darkjield observation. Dark-field Ultracondenser

Dry dark{ield condenser

47 S T A N D A R D W L r e s e a r c h m i c r o s c o p e w j t h 6 v , 1 Sw i n t e g r a l i l l u m i n a t o r , p a n c r a t i c c o n d e n s e r , P l a n a c h r o m a t s ,O P T O V A R a n d K p ' i w i d e - a n g l e e y e p i e c e s

Surveyof opticalsystems 48 forthe Objectives ightmicroscope itted-l transm

Achromats

D e s i gn a t io n

O O

O

O

Achromat,3.2x,0.07N.A. Achromat,6.3x,0.16 N.A. A c h r o m a t , 1 0 x , 0 . 2N2. A . Achromat.16x.0.32N.A. Achromat,25x,0.45N.A. Achromat,40x,0.65N.A. Achromat,63x,0.80N.A. Achromat,40x,0.75N.A.,waterl) Achromat,40x,0.85N.A.,oil Achromat,40x,0.85N.A.,oil A c h r o m a1t 0 0 x 1 , . 2 5N . A . o , il Achromat,100x,1.25N.A.,oil,with iris3)

T a b l e8 l ni ti a l magnrfication

N.A.

Focal Ie n g t h mm

Working Cover-glass d i s t a n c e ? )t h i c k n e s s C a t a l o g mm No. mm

3.2x 0.07 34.9 30 6.5x

0.16

24.4 10.3

10.2x 0.22 16.7 16.2x 0.32 25.4x 0.45 40.8x 0.65

10.8 7.0 4.5

63.3x 0.80

3.0

40.4x 0.75 40.0x 0.85 39.2x 0.85 98.8x 1 . 2 5 98.8x 1 . 2 5

4.6 4.6 4.7 1.9 1.9

5.0 3.5 1.0

0.17 0.47 0j7 0j4 0j7 1.6 0.17 0.35 0j7 0.35 1.5 0.09 0j7 0.09 0.17

460100 460300 460400 46 05 00 46 06 00 46 07 00 4 60 80 0 461702 461706 46 1708 4 6 1 90 0 46 19 06

1) For Achromat, 40x, 0.75N.A., water, a clip-on cap 461790is supplied. ,) The working distance is the clear distance between the front lens of the objective used and the specimen (upper surface of covet g lass). 3) Objective with iris for stopping down the aperture in dark-field work. 4 ) O b j e c t i v e w i t h c o r r e c t i o n c o l l a r c a n b e u s e d f o r c o v e r - g l a s s e s w i t h t h i c k n e s s f r o m 1 . 1t o 1 . 5 m m . 5) Special objective, e. 9., for STANDARD UPL, for work with specimen in thick-walled chambers.

49

Planachromats

Designation

Table 9 I ni t i a l magnif i c a t i on

* Planachromat, 2.5x,0.8N.A. 2.6x * Planachromat 6.3x,0.16N.A. 6.26x O Planachromat, tOx, OZZtrt* 10.0x f Planachromat, 16x,0.35N.A. 16.1x Planachrom at, 25x,0.45 N.A. O* Planachromat, 40x, 0.65l{A 40.8x LD-PIanachromat, 40x,0.60N.A.,corr.o; 3g.9x f P l a n a c h r o m a1t0 0 x ,1 . 2 5N . A . ,o i t - 1 0 0 - 6 x Planachromat, 100x,1.25N.A.,oil, with iris3) 100.6x Generallyrecommendedfor a seriesoJ O four objectives + five objectives

N.A

Focal length mm

W o r k i n g Cover-glass d istance,) th ickness C a t a l o g mm mm No.

0.08 54.5 8.7 0 . 1 6 27j 4.9 0.22 15.8 4.8 0.35 10.4 2.7 0.45 7.0 1.4 0.65 4 . 1 3 0 . 7 0.60 4 . 1 1 . 5 .% 1 . 6 6 0J9

46 03 10 460410 460510 0.17 460610 0 . 1 7 4 60 71 0 1 . 1 - ' 1 . 546 07 15s) 0 . 1 7 4 6 1 91 0

1.25

0.17

T

1 . 6 6 0.09

4 6 1 91 6

50

T a b l e1 0

NEOFLUARS l n l t i aI magn if l c a t io n

+ NEOFLUAR.6.3x.0.20N.A. 6.4x NEOFLUAR,10x,0.30N.A. 10.2x + N E O F L U A R1, 6 x ,0 . 4 0N . A . 16.1x 25x, N.A. NEOFLUAR, 0.60 + NEOFLUAR.40x. 0.75N.A. 40.5x Plan-NEOFLUAR, 63x,0.90N.A., corr.4) 62.9x N E O F L U A R6,3 x ,1 . 2 5N . A . ,o i l 62.6x

+ NEOFLUAR 1 0, 0 x1, . 3 0N . A .o, i l

N.A

Focal Ie n g t h mm

Working Cover-glass distancer) thickness Catalog mm No. mm

0.20 23.6 10.8 0.30 16.4 4.0 0.17 0 . 4 0 1 0 . 8 0.9 7 . 1 0 . 5 4 0.17 0.60 4.5 0.33 0.17 0.75 0.90 1.25

100.0x 1.25

46ffi24 460420 460520 460620 460720

2.7 0 . 0 9 0 . 1 1 - 0 . 2 34 6 0 8 1 2 - 9 9 0 3 461820 2,8 0.65 0j7 1.92 0.24 0j7 461920

51

Planapochromats

D e s i gn a t io n

Pianapochromat, 4x, 0.16N.A. Planapochromat, 1Oxo 0.32N.A. Planapochromat, 25x, 0.65N.A. Planapochromat 40x, 0.95N.A.,corr.4\ Planapochromat, 40x, 1.0 N.A.,o i l , with iris3) Planapochromat, 63x, 1.4 N.A.,oil P l a n a p o c h r o m a1t 0, 0 x ,1 . 3N . A . ,o i l , P l a n a p o c h r o m a1t0, 0 x ,1 . 3N . A . ,o i l , with iris3)

T a b l e1 1 lnitial magnrfication

N.A

Focal length mm

4.1x 0.16 35.1 10.0x 0.32 14.6 25.3x 0.65 6.3 40.4x 0.95 4.25 100.2x t . J 62.1x 1 . 4 100.2x 1 . 3 40.1x

1.0

Working Cover-glass distancer) tickness mm mm

2.5 0.35 0j4 0.09

1 . 6 30 . 0 9

Catalog No.

460240 0.17 460440 0.17 46 06 40 0 . 11 - 0 . 2 3 4607 42

1.63 0.09

0.17 0.17 0.17

4 6 1 94 6 46 1840 461940

4.05 0.22

0.17

461746

2.57 0.09

f) The working distance is the clear distance between the front lens of the objective used and the specimen (upper surface of cover glass). ,) Objective with iris for stopping down the aperture in dark-fleld work. ') uolecllve wiln correctlon collar can be used for cover-glasses with thickness from 0.11to 0.23 mm.

52

Phase-contrastobjectives

These objectives contain an annular phase plate in which phaseshift and absorption are matchedso that optimumimageswill be obtainedwith the majority of specimens for which the phase-contrasttechniquecan be used to advantage.For specialproblems, objectiveswith speciallymatchedabsorption can be made to order. Detailswill be supplied on request. lf phase-contrastobjectives are used for bright-fieldwork, a more or less noticeable but generallyhardly disturbingloss of contrast must be expected, depending on the objectivetype chosen.This effectwillbe least noticeable with the Ph NEOFLUARSand For dark-fieldobservation Planapochromats. phase-contrastobjectivesare generallynot to be recommended.

53 Phase-contrast objectives

Initialmagnrfication

D e s ig n a t i o n

Achromat, Achromat, Achromat,

10x,0.22N.A..Ph1 4 0 x , 0 . 6 5N . A . P , h2 40x,0.75N.A.,water, Ph2 Achromat, 4 0 x , 0 . 8 5N . A . ,o i l . P h 3 Achromat, 1 0 0 x , 1 . 2N 5 .A.o , i t ,P h 3 Planachromat, 25x,0,45N.A.,Ph2 LD-Planachromat, 40x,0.60 N.A.,corr.,

N.A.

Focal tength mm

W o r k i n g Cover-g I ass di s t a n c e t h i c k n e s s mm mm

Catalog No.

10.2x 0.22 167 5.0 40.8x 0.65 4.5 0.47 40.4x 0.75 4 . 6 1 . 6

0.17 0.17

46 04 01 460701 46 1703

39.2x 0.85 98.8x1.25 25.2x 0.45 39.9x 0.60

4.7 1.9 7.0 4.1

1.5 0.17 0.17 1.1-1.5

4 6 1 70 9 46 19 01 460611 4 6 0 71 6 .

40x,0.65N.A.,Ph2

40.8x 0.65

4j3 0.7

63x,0.90 N.A.,corr., Ph3

63.4x0.90 2 . 7 0 . 0 9

0.17 0j7

460711 460813

Ph2 Planachromat, Planachromat,

T a b l e1 2

0.35 0.09 1.4 1.5

Planachromat, 1 0 0 x 1 , . 2 5N . A . o , i t ,p h 3 1 0 0 . 6 x1 . 2 5 1 . 6 60 . 0 9 NEOFLUAR, 1 6 x , 0 . 4 0N . A . P , h2 1 6 . 1 x0 . 4 0 1 0 . 8 0 . 9 NEOFLUAR. 25x,0.60N.A.,Ph2 25.2x 0.60 7.1 0.54 NEOFLUAR. 40x,0.75N.A.,Ph2 40.5x 0.75 4.5 0.33 Plan-NEOFLUAR, 63x,0.90 N.A.,corr., 62.gx0.90 2.7 0.09

0.17 461911 0.17 460521 0.17 460621 0.17 460721 0.11-0.23 46 08 13_9903

NEOFLUAR, 6 3 x , 1 . 2 5N . A . o , i l ,P h 3 6 2 . 6 x 1 . 2 5 NEOFLUAR. 100x,1.30N.A.,oit, Ph3 100.2x1.25 Planapochromai,25x,0.65N.A.,Ph2 25.3x 0.65 Planapochromat,40x,0.95N.A.,corr., 40.4x 0.95 Ph3 Planapochromat,40x,1.0N.A.,oil, 4 0 . 1 x1 . 0 w i t h i r i s ,p h 3 P l a n a p o c h r o m a t6, 3 x , 1 . 4N . A . ,o i l , p h 3 A Z . l x @ Planapochromat, 100x,1.30N.A.,oil, ph 3 100.2x1 a

0.17 4 6 1 82 1 0.17 4 6 1 92 1 0.17 4606 41 0.11-0.23 460743

Ph3

-

2.8 0.65 1.92 0.24 6.3 0j4 4.25 0.09

4.050.22 0.17

Special objective, e' 9., for STANDARD UPL, for work with specimens in thick-walled cnamoers.

461747 4 6 1 84 1

54 POLZ objectives for polarized-lightmicroscopy

The objectiveslistedbeloware strain-free and have centeringmounts.

T a b l e1 3

D e s i gn a t i o n

O*Planachromat, 2.5x,0.08N.A.,POL Z 1 0 x . 0 . 2N 2 . A .P . OLZ Of Achromat, -FNEOFLUAR, 25x,0.60N.A.,POLZ 4 0 x , 0 . 8 5N . A . ,P O L Z O*Achromat, N E O F L U A R , 6 3 x , 0 . 9 0N . A . ,P O L Z 1 0 0 x ,1 . 2 5N . A . ,o i l , P O L Z O*Achromat, Generallyrecommendedfor a seriesof O four objectives + five objectives

l ni t i a l magnification

2.6x 10.2x 25.2x 39.4x

N.A.

Focal length mm

Working distance mm

0.08 0.22 0.60 0.85

54.5 16.7 7.1 4.7

8.7 5.0 0.54 0.36

63.3x 0.90

3.0 0.12

98.8x 1.25

1.9 0.09

thickness mm

Catalog No.

0j7 0j7 0j7 0j7

46 0'118 46 04 08 460628 46 07 08 460828 4 6 1 90 8

55 UDAchromats

w

w w

ryw

UD achromatsare objectivesspeciallydesignedfor usewith the universalrotarystage. This aid for spatial orientationof the spec i m e n i s p r i m a r i l yu s e d i n p o l a r i z e d - l i E h mti croscopy. The objectivesare attachedto the polarizingmicroscopewith the aid of a centera b l e o b j e c t i v ec h a n g e r " T h e i n i t i a l m a g n i f i c a t i o na n d n u m e r i c a l apertureindicatedon the UD achromatshold f o r u s e i n c o n j u n c t i o nw i t h h e m i s p h e r ew s ith a refractiveindex of 1.555. lf the objectives are suitedfor "conoscopic"observation, they a r e m a r k e d " C " . U n d e r o r t h o s c o p i co b s e r vation,the extinctionpositionof a crysialcan be recognizedif the apertureof the objective is reduced. This is why two funnel stops are s u p p l i e dw i t h e v e r y U D a c h r o m a to f h i g h e r m a g n i f i c a t i otnh a n 1 6 x . U s e dw i t h o u t h e m i s p h e r e t h, e U D a c n r o m a t s o f f e r a p a r t i c u l a r l yl o n g w o r k i n g d i s tance. Due to their overall length of 33 mm they must be attachedto the microscopeby m e a n so f t h e a d a p t e rr i n g 4 6 2 9 9 1 .

56 UDAdrromats for universalrotarystage,withoutspecimen protection, parfocalized for 33 mm

T a b l e1 4

T e c h n i c adl a t af o r u s i n gt h e o b j e c t i v e sw i t h a n d w i t h o u th e m i s p h e r e lnitial Focal Refractive Working Designation

AchromatUD, 6 . 3 x , 0 . 1N 2. A .

AchromatUD, 16x.0.17 N.A.

magnification

3.7

N.A.

length mm

distance mm

Catalog No. of objective

0.07

30.4

19.0

462042

6.1

0j2 0.13

41.8 44.6

13.5 13.5

25.5 24.8

6.5

6.1

012 0.13

9.6

0.11

15.6

13.5

14.9 15.8

o.17

14.9 15.8

0.17 0.18

10.0

Achromat UD, 12.7 20x,0.57N.A. C** 19.7

0.38

12.6

0.18

21.0

0.57 0.61

AchromatUD. 25.8

0.41

40x,0.65N.A.C** 40.2 42.7

0.64 0.68

t Maximum permissible deviaiion 0.002 '. Suitable for conoscopic observation.

11.2 10.7

index rr"

Radius

Catalog No. of hemisphere

1.517 1.517 1.648 1.517 1.517 1.648

5.52 5.52 5.52 12.56 12.56 12.56

47 3824 47 3825 47 3826 47 3827 47 3828 47 3829

5.52 5.52 12.56 12.56

47 3824 47 3825 47 3826 47 3827 47 3828 47 3829

462044 1.517 1.557 1.648 1.517 1.517 1.648

10 10

10.5

4620 45 1.517 1.517 1.648

47 3824 5.52

47 3825 47 3826

462046

6.9

3.7

12.56

1.5 1.5

1.517 1.517 1.648

5.52 5.52

47 3824 47 3825 47 3826

57 The 1x Planachromat is the objectivewith the lowestinitialmagnif i c a t i o na n d b u i l t - i nf i e l d l e n s . l t i s n o t o a r focalized with the other objectives. For polarized-lighm t i c r o s c o p yw e s e l e c t t h e most strain-freeobiectives.

The 1.6x-5x Planachromat is particularlysuitable for measuring purposes, because the magnification of the aerial image can be accuratelyadapted to the graduationof the micrometerdisk. The objective is used with a condenserwhose front lens is swung out of the light path. Ref o c u s i n gi s r e q u i r e di f t h e m a g n i f i c a t i o no f the objectiveis changed. The 32x Planachromat is an objective specially designed for our RevolverMicroprojector.lts front-lensmount is finished in black to avoid stray light. lf necessary,it may be used on any other microscope.

Special-purposeobjectives for the normaltransmitted-light microscope

Designation

l ni t i a l magnrf i c a toi n

Planachromat, 1x. 0.04N.A. 1.08x lx,0.04 N.A.,POL 1.08x 1 . 6 x - 5 x , 0 . 0 3 - 0 . 1N . A . 1.6x- 5x 3 2 x , 0 . 6 5N . A . 32.2x 63x,0.90N.A.,oD (for uncoveredspecimens) 63.0x

Table 15 Focal length mm

0.04

134.7

Working distance mm

4.4

0.04 134.7 4.4 0.03 0.1 4 1 . 2 - 2 0 . 8 3 2 - 1 . 5 0.65 5.6 0.3 0.90

3.0

Cover-glass thickness Catalog mm No.

0.09

0.17

462010 4 62 01 1 4 62 01 3 462016 46 08 60

5B ULTRAFLUARS

These are special-purpose objectives equally suited for observationby ultraviolet a n d v i s i b l el i g h t . T h e y a r e a c h r o m a t i cf o r a rangefrom 230to 700 mpz.Thus there is pract i c a l l yn o s h i f t i n f o c u s w h e n c h a n g i n gf r o m one wavelengthto another. The objectives are corrected for 0.35 mm thick quartz ( H o m o s i l )c o v e r g l a s s e s a n d d e s i g n e df o r glycerinimmersion,exceptthe ULTRAFLUAR, 1 0 x .0 . 2 0N . A . .4 6 2 0 5 9 . These objectives are very sensitive to fluctuationsof temperature.

T a b l e1 6

Designation

ULTRAFLUAR, 1 0 x , 0 . 2 0N . A .

N.A.,glyc. 32x,0.40

F o r w a v e l e n g t h 2 8 0m p lnitial Focal Iengtl magniN.A. fication mm

Working distance mm

10.0x 0.20 16.4

7.4

32.0x 0.40 6.0

0.45

For wavelength 546 mt Focal length fication N.A. mm

lnitial Covergrass magnit hi c k n e s s

9.4

0.35

Catalog No.

0.19 17.5 462058

30.0 0.38 6.4 462060

0.35 98.0 0.81 1.93 462063 100x,0.85N.A.,91yc. 103.5x 0.85 1.79 0.12 87.8 1.15 2.00 46 20 64 100x,1.25N.A.,glyc. 100.9x 1.25 1.77 0.07 0.35 0.35 30.0 0.38 6.4 462070 32x,0.40N.A.,glyc.,Ph 32.0x 0.40 6.0 0.35 98.0 0.80 1.93 46 20 73 100x,0.85N.A.,glyc.,Ph 103.5x 0.85 1.79 0.12 9.4 0.19 17.5 462059 1 0 x , 0 . 2 0N . A . P , OL 10.0x O.2O 16.4 7.4 30.0 0.38 6.4 462061 0.35 32x,0.40N.A.,glyc.,POL 32.0x 0.40 6.0 0.46 87.8 1.15 2.00 462065 1 0 0 x , 1 . 2 5 N . Ag.l,y c . ,P O L 1 0 0 . 9 x 1 . 2 5 1 . 7 7 0 . 0 7 0.35 465557,see page 93. For achromatic-aplanatic ULTRAFLUAR-condenser

59 Jamin-Lebedeff transmitted-light Three objectivesof the AchromatpOL Int interference-equipmenttype and a specially selected condenser c o n v e r t a n y o f o u r l a r g e p o l a r i z i n gm i c r o scopesinto an interferencemicroscope.This allowsthe refractiveindex,thicknessand dry mass of discrete objects(i. e. objects which do not cover a continuousarea) to be d e t e r m i n e d .T h e b e a m s p l i t t e r i n t h e c o n denser separatesthe rneasuringand comp a r i s o nb e a m s . T h e b e a m c o m b i n e ri n t h e objectivecausesthe two beamsto interfere. For furtherdetailssee booklet41-560.

Interferenceattachments

i nterference attachment

ll ill

with Achromat P O Ll n l

10x,0.22N.A. 40x, 0.65N.A. 1 0 0 x ,1 . 0N . A . ,o i l

T a b l e1 7

Working dislance mm

2.26

0.2 0.08

Distance between measuring and comparison beams mm

Catalog No. for STANDARD microscopes

Catalog No. for UNIVERSAL, PHOTOMICROSCOPE, ULTRAPHOT

0.5 0.17 0.05

47 4403 47 4406 47 4408

47 4413 4744 16 47 4418

60 Objectives microscopy for reflected-light All our microscopesfor opaquework are c o m p u t e df o r u n c o v e r e d s p e c i m e n s .I n v i e w o f t h e h e i g h to f t h e v e r t i c a li l l u m i n a t o r to be insertedbetweenthe tube and the objective they have a relativelyshort parfocal d i s t a n c eo f 3 3 m m .T h e i ri n i t i a l m a g n i f i c a t i o n s partlydeviatefrom our usualstandardvalues of 50x, in view of the standardmagnifications 100x,200x, 500x and 1000x used in metalI u r g i c a lw o r k . With few exceptions,all our reflectedlight objectivesare designedas flat{ield objectives. In the systemssuppliedsince 1965 special care has been taken to eliminatereflectionsat glass-to-airsurfacesby suitable shapingand coating of the lenses. This has beensurprisinglysuccessfulin the newseries of EPIPLANobjectives.

61 EPIPLANHD objectives For dark-field observationthe objective for bright{ield and dark-fieldobservation p r o p e ri s b u i l ti n t oa c o n c e n t r i cm i r r o ro r l e n s b y i n c i d e n tl i g h t system. This reduces the free working distance of the three low-powersystems.These objectivesdo not have the Whitworththread 0.8"xl/se"but the M24x0.75screw thread.

T a b l e1 8

D e s i gn a t i o n

Initial magnification

N.A.

Focal length mm

E P I P L A N 4 x , 0 . 1 0N . A . ,H D 4.07x 0.1 36.3 E P I P L A N 8 x , 0 . 2 0N . A . ,H D 7.96x 0.2 18.7 E P I P L A N 1 6 x ,0 . 3 5N . A . ,H D 16.06x 0.35 10.4 E P I P L A N 4 0 x , 0 . 8 5N . A . ,H D 40.56x 0.85 4.6 EPIPLAN 8Ox,0.95N.A.,HD 80.7x 0.95 2.25 E P I P L A N1 0 0 x ,1 . 2 5N . A . ,o i t , H D 100.6x 1 . 2 5 1.66

Working distance mm

0.23 0.09 0.25

Coverglass

Catalog No. Objective thickness for mm noseprece

Catalog No. Objective with change ring (46 62 55)

460269 480269 46 03 69 48 03 69 46 05 69 48 05 69 4607 69 4807 69 46 08 69 48 08 69 461969481969

62 EPIPLANobjectives To permit rapid change between the for bright-fieldobservationby incidentlight standardmagnificationsused in metallography, these objectives are mounted on the t y p e l l l D v e r t i c a li l l u m i n a t o4r 6 6 2 4 7 .O n t h e U N I V E R S Am L i c r o s c o p et ,h e P H O T O M I C R O SCOPEand the ULTRAPHOTcamera microof 50x,100x,200x,500x scope magnifications and 1000xcan be achievedwith Kpl 10x eyeoieces.

T a b l e1 9

Designation

E P I P L A N ,4 x , 0 . 1 N . A . E P I P L A N ,8 x , 0 . 2 N . A . E P I P L A N1, 6 x , 0 . 3 5N . A . E P I P L A N4, 0 x , 0 . 8 5N . A . EPIPLAN,80x,0.95N.A.

lnitial m a g n i fi c a t i o n

4.07x 7.96x 16.06x 40.56x

80.7x

N.A

0.1 0.2 0.35 0.85

0.95

Focal Iength mm

Working d i stance mm

36.3

9.0

18.8 10.4 4.6

7.2 2.8

2.25

0.23 0.09

Cover-glass thi ckness mm

63 LD-EPIPLAN objectives have an extra long working distance. They are requiredwheneverthe objectivemust be protectedagainstthe effectsof heat,caustic vapors,etc.,by meansof a glassplate placed i n t h e o b j e c t f i e l d . L D - E P I P L A No b j e c t i v e s w i t h t h e d e s i g n a t i o nD : 1 . 5 m m a r e s u p l i e dw i t h a 1 . 5m m t h i c kp r o t e c t i v ec a p . l f t h e specimenis coveredby a quarlz glass,e. 9., a s i s u s u a li n w o r k w i t h h e a t i n gs t a g e s t, h e n the quartz plate providesthe necessaryprotection in place of the protectivecap. D u e t o t h e i r l o n g w o r k i n g d i s t a n c e ,t h e LD-EPIPLANobjectivesare especiallysuitable as substagecondensers.They are used f o r t h i s p u r p o s ep r i m a r i l yi n w o r k w i t h t h e M icroscopePhotometer.

T a b l e2 0

D e s ig n a t io n

lnitial magn if i c a t lo n

L D - E P I P L A N4, x , 0 . 1N . A . 4.06x L D - E P I P L A N8, x , 0 . 2N . A . 7.94x 0 L D - E P I P L A N' 1, 6 x , 0 . 3N .A. 16x LD-EPIPLAN, 40x,0.60N.A. 40.1x LD-EPIPLAN, 40x,0.60N.A. 40.1x LD-EPlPLAN,40x,0.60N.A., Pol* 40.1x

Focal length mm

0.1 0.2

Working distance (mm) Coverwith l.5mm with1.5mm glass protective thickness coverglass cap mm

36.3

7.5 5.7

18.7 6.2 0.30 10.1 4.1 0.60 4 . 1 3.4 0.60 4 . 1 3 . 1

3.6 2.3

0.60

2.3

4.1

J.+

t.3

1.5 t.c t.c

Objective Catalog No.

462101 462102 462143 462104 462097

Protective cap, D1.5 No.

462911 462912 462913 462914

462124 462916

F o r t h e N o m a r s k i i n t e r f e r e n c e - c o n t r a s tm e t h o d i n r e f l e c t e d l i g h t u s e t h i s o b j e c t i v e , m o u n t e d a l m o s t s t r a i n J r e e , w i t h p r o t e c t i v e c a p D 1 . 5 ( 4 6 2 9 1 6 )a n d i n t e r f e r e n c e - c o n t r a s t a t t a c h m e n t ( 4 7 4 4 6 4 \ .

64 EPIPLANPOL obiectives The completely sirain-free bright-field for polarized-lightmicroscopyand objectives are designed for polarized-light method work, e. g. in ore microscopyor in connection the Nomarskiinterference-contrast w i t h i n c i d e n tl i g h t ( C N R Sl i c e n c e ) with opticallyanisotropicmetal phases.They are attachedto the type llA, ll ST, Il C and ll E vertical illuminatorsby meansof the change ring 466256 in which they can be centered. As comparedwith dry objectives,immercentering change ring sion objectives result in enhanced image contrastbecausereflectionsat the first surEPIPLAN POL objective with thread W 0.8" face of the front lens are made impossible and the differencesbetween the reflectivity and the intrinsic color of certain objects stand out more clearly against oil than a g a i n s ta i r . lf a vertical illuminatoris to be used for I nterference-contrast Nomarski interference-contrast method, the attachment with thread W 0.8" is a special interference-contrast attachment f o r E P I P L A NP O Lo b j e c t i v e neededfor each EPIPLANPOL objective.

T a b l e2 1

Designation

E P I P L A N ,4 x , 0 . 1 0N . A . ,P O L E P I P L A N ,8 x , 0 . 2 0N . A . ,P O L , OL E P l P L A N1, 6 x ,0 . 3 5N . A . P EPIPLAN,40x,0.85N.A.,POL EPIPLAN,80x,0.95N.A.,POL E P I P L A N ,4 x , 0 . 1 0N . A . ,P O L ,o i l , O L ,o i l E P I P L A N ,8 x , 0 . 2 0N . A . P 16x,0.40 N.A., POL,oil Epi-Achromat, N.A.,POL,oil Epi-Achromat,40x,0.85 1 0 0 x 1 , . 2 5 N . A .P , O L ,o i l EPIPLAN,

lnitial magnification

N.A.

4.07x 0.1 7.96x 16.06x 40.56x 80.7x

0.2 0.35 0.85 0.95

4.07x 0.1 7.96x 16.0x 40.0x 98.8x

Focal length mm

Working d istance mm

36.3 9.05 18.7 7.1 10.4 2.7 4.6 0.23

2.3 0.09 36.3 0.3

18.7 0.3 0.2 0.40 10.0 0.85 0.85 4.6 0.5 1 . 2 5 1.94 0.28

Coverglass thicknessCatalogNo. obiective mm

462001 462002 462003 462004 462080

C a t a l o gN o . Interferencecontrast attachment"

47 4492 47 4492 47 4493 47 4494 47 4495

462006 462007 462008 462009 462005 474496

T o b e u s e do n T y p e l l v e r t i c a li l l u m i n a t o r sw i t h c h a n g er i n g 4 6 6 2 5 8 .O n v e r t i c a li l l u m i n a t o r sw i t h r e v o l v i n gn o s e p i e c e( T y p e sl A , co z edda.p t e r r i n g 4 6 2 9 9 6 4 r/ r e s p o n d i n g o b . i e c t i v e s a r e p a r f o c a l i A f l l A , l l l C ) t h e i n t e r f e r e n c e - c o n t r a s t a t t a c h m e n t s 4 T 4 4a9n3d/ 9 serves as connection

65 EPIPLANStM objectives

ThesearedesignedfortheSTANDARDUM i n v e r t e d m e t a l l u r g i c a lm i c r o s c o p e . S i n c e they fit into the revolvingnosepieceof the s t a n d a r dt r a n s m i i t e d - l i g hmt i c r o s c o p e sa n d are parfocalizedwith the transmitted-light objectives,they may also be usedfor examini n g u n c o v e r e d t r a n s p a r e nst p e c i m e n si n a l l c a s e sw h e r eo r d i n a r yt r a n s m i t t e d - l i gohbt jectiveswould give unsatisfactory resultsdue to the lack of a cover glass. E P I P L A NS t M P h o b j e c t i v e sc a n b e u s e d for phasework if the diaphragminsert467059 is placed in the base of the invertedmetall u r g i c a lm i c r o s c o p e .E v e r yE P I P L A NS t M P h o b j e c t i v ei s s u p p l i e dw i t h a n a n n u l a r d i a p h r a g mw h i c hc a n b e c e n t e r e di n t h i s i n s e r t .

Table 22

D e s jg n a t io n

E P I P L A NS t M , 4 x . 0 . 1 0N . A . EPIPLANStM, 8x, 0.20N.A. E P I P L A NS t M , 1 6 x ,0 . 3 5N . A . EPIPLANStM. 40x.0.85N.A. EPIPLANStM, 80x,0.95N.A. E P I P L A NS t M , 1 0 0 x ,1 . 2 5N . A . ,o i l E P I P L A NS t M , 1 6 x ,0 . 3 5N . A . ,P h EPIPLANStM, 40x, 0.85N.A.,Ph E P I P L A NS t M , 1 0 0 x ,1 . 2 5N . A . ,o i t , p h

lnitial magnrfi c a t i o n

N.A.

4.07x 7.96x 16.06x 40.56x 80.7x 100.7x 16.06x 40.56x

0.10 0.20 0.35 0.85 0.95 1.25 0.35 0.85

Focal Ie n g t h mm

Working di s t a n c e mm

36.3 18.8 10.4 4.6

9.0 7.2 2.8

462031 462032 462033 462034

2.25 0.09

1.7 10.4 4.6 100.7x 1.25 1 . 7

Cover-glass thi ckness mm Catalog No

0.25 2.8

0.23 0.25

462035 462036 462037 462038 462039

66 EPIPLANPh objectives These objectivescontain annular phase for phase-contrast work platesspeciallyadaptedto the requirements utithverticalilluminators of incident-lig ht phase-contrastm icroscopy. They are used in conjunctionwith a phasecontrastdiaphragminsertwhichamongother things holds three suitable annular diap h r a g m so n a c h a n g e d i s k . EPIPLAN Ph objectives have the same W 0.8"xl /ze"screwthreadas the transmittedlight objectives. They are not suitable for combination with our phase-contrastcondensersfor transmittedlight.

Table 23

EPIPLANPh objectives

Designation

I ni t i aI magnif i c a t io n

E P I P L A N , 1 6 x ,0 . 3 5N . A . ,P h EPIPLAN, 40x,0.85N.A.,Ph E P I P L A N1. 0 0 x .1 . 2 5N . A . .o i l . P h

16.04x 40.56x 100.7x

N.A.

Focal Ie n g t h mm

0.35 10.4 0.85 1.25

4.6 1.62

Working d istance mm

Cover-gIass thi ckness mm

2.8

0.23 0.25

Phase-contrastdiaphragm inserl 472073 for vertical illuminator type ll G with single objective changer, Phase-contrastdiaphragm i^sert 472072 for vertical illuminator iype lll C with a revolving nosepiece can be combined with the UNIVERSAL and ULTRAPHOT microscopes

C a t a l o gN o

462027 462028 462029

67 Antifleximmersionobjectives

ln the case of reflected-lightbright{ield i l l u m i n a t i o np,a r t o f t h e i l l u m i n a t i n tgi g h t i s always refiected back to the image plane from the glass-airsurfacesof the objective before it has fully passedthrough the latter. The amountof light that is reflecteddepends on the type of objectiveand the adjustment of the light path. lt may even happenthat an image of the objective aperture becomes v i s i b l e . T h i s e f f e c ti s p a r t i c u l a r l yd i s t u r b i n g when viewing objects of low reflectivity.lt c a n b e e l i m i n a t e db y u s i n gp o l a r i z e dl i g h tf o r i l l u m i n a t i o nw, h o s e s t a t e o f p o l a r i z a t i o ni s hardlychangedby specularreflection.When a n a n a l y z e ri n t h e i i g h t p a t h i s o r i e n t e ds o t h a t i t s p l a n eo f v i b r a t i o ni s p e r p e n d i c u l at ro that of the light reflectedfrom the lens surf a c e s , t h i s l i g h t c a n b e e x t i n g u i s h e d .T h e light diffusely reflectedfrom the specimen surface,however,will pass through the analyzer practicallyunattenuatedbecause it is depolarizedin the courseof diffusereflection. In the case of specular reflectors-which m o s t p o l i s h e ds p e c i m e n sa r e - t h i s m e t h o di s p o s s i b l eo n l y i f a s u i t a b l yo r i e n t e dc, i r c u l a r l y polarizingf ilter is insertedbetweenthe specim e n a n d t h e o b j e c t i v e .S o m e o f o u r b r i g h t field reflected-lightobjectivesare provided with such filters. They are then called "Antiflex objectives". These are availablein the forrn of EPIPLANand achromaticobjectives f o r i n c i d e n t - l i g hwt o r k w i t h o i l a n d m e t h y l e n e iodide. Antiflex immersion objectives give part i c u l a rh i g h c o n t r a s if o r b r i g h t - f i e l di n c i d e n t light observations,because the use of an i m m e r s i o nm e d i u me l i m i n a t e sa l l r e f l e c t i o n s at the first surfaceof the front lens,while the Antiflexsystemeliminatesall reflectionfrom the surfacesof all other lens elements,and because the differencesof reflectlvityand intrinsic color of certain objects are more p r o n o u n c e da n d m o r e c l e a r l yv i s i b l e i n o i l

6B than in air. These objectivesare especially suitablefor objects of low to medium reflectivity (coal petrography)and specimensof varyingreflectivity(weakto stronglyabsorbing or refracting).Methyleneiodide immersion objectivesgenerallyproduce the same resultas the correspondingobjectivesfor oil immersion,but are even bettersuitedfor objects of extremelylow reflectivity(coal petrography). T h e c i r c u l a r l yp o l a r i z i n gf i l t e r l o c a t e di n front of their lens elementsmakes these objectives unsuitable for certain measuring techniques,e. g. for the polarized-lightanalysis of the vibrationalstate of polarizedreflected light.

Table 24

Antiflex immersion objectives

D e s ig n a t io n

EPIPLAN-Antiflex, 8 x , 0 . 2 N . A . ,o i l Antiflex-Epi-Achromat, 16x,0.40N.A.,oil Antiflex-Epi-Achromat, 4 0 x . 0 . 6 5N . A . .o i l EPIPLAN-Antif lex, 2.5x,0.08N.A.,methyleneiodide EPIPLAN-Antiflex, 4x, 0.1 N.A.,methyleneiodide EPIPLAN-Antif lex, 8x,0.2 N.A.,methyleneiodide A ntiflex-Epi-Achromat, 16x,0.40N.A.,methyleneiodide Antiflex-Epi-Ach romat, 40x,0.65N.A.,methyleneiodide

lnitial magnrfication

Catalog No. Objective for nosepiece

Catalog No. Objective with change ring

N.A.

7.9x

0.2

18.75 0.4

461364

481364

16.0x

0.4

10.0 0.45

461554

481554

40.0x

0.65

4.6

0.5

461754

4817 54

2.9x

0.08

54.8

0.3

46 1163

48 1163

4.1x

0.1

36.3 0.4

461263

7.9x

0.2

18.75 0.4

46 13 63

48 13 63

16.2x

0.4

10.0 0.35

46 1553

48 15 53

39.6x

0.65

461753

4817 53

4.6

Working distance mm

Coverglass

Focal length mm

0.25

thickness mm

Photomicrographic objectives LUMINARSwith iris diaphragm

69

for photographyby transmittedor incident l i g h t ,w i t h d a r k - f i e l di l l u m i n a t i o pn r o d u c e db y illuminators. stereomicroscooe

Table 25

Designation

1 6m m L U M I N A R

Focal length mm

Distance between focal plane and front lens vertex (mm)

For infinite object distance Relative objectN.A. aperture side

16.1 0.2

image side

Magnifications obtainable

with ULTRAPHOT"

1 : 2 . 5 1 0 . ' 1 1 1 . 5 50x-70x

with UNIVERSAL mr c r o s c o p e , PHOTOM I C R O S C O P E C a t a l o gN o

14x-22x

462511

8x-14x

462513

4x-Bx

462515

2x-4x

462517

40x-55x

25 mm LUMINAR

2 6 . 0 0 . 1 4 1: 3 . 5 2 1 . 9 2 3 0

31x-43x 25x-34x

40 mm LUMINAR

3 9 . 9 0 . 1 1 1 : 4 . 5 3 4 . 9 2 7 . 9 20x-27x 16x-22x

63 mm LUMINAR

63.4 0.11

1:4.5 54.8 45.0

1 1. 5 x - 1 6 x 9.5x-12.5x

1 0 0m m L U M I N A R 1 0 0m m L U M I N A R f o r L u m i n a rh e a d 2 . 5 xt o 5 x L U M I N A R for ULTRAPHOT

102.3 0.08 1:6.3 76.2 91.8 102.3 0.08 1 :6.3 76.2 91.8 6.5x-9.5x

462519 1.5x-28x 462529

5.3x-7.5x

variable

0.04/ 0.05

2.5x-3.6x

462531

3.6x-5x

* A c o n t i n u o u s s e r i e s o f m a g n i f i c a t i o n s c a n b e a c h i e v e d w i t h t h e U L T R A P H O T i f t h e O . 8 xa u x i l i a r y s y s t e m , C a t a l o g N o . 4 6 2 5 8 0 , i e employed. The magnifications corresponding to this combination appear in small print.

70 1 0 0m m L U M I N A R

T h e 1 0 0 m m L U M I N A RC , a t . N o .4 62 5 1 9 , has an M 44x0.75screw threadat eitherend. Thus, when the protectivering in front has been removed,the objective may also be used in an inverted position to secure reduced scales.

100mm LUMINAR

T h e 1 0 0 m m L U M I N A RC , a t .N o .4 6 2 5 2 9 , is basicallythe sameobjeciiveas No. 462519, With its special mount it can be attachedto the Luminarhead of the ULTRAPHOT.

to 5x LUMINAR

The 2.5x to 5x LUMTNARis a speciatpurpose objective designed for very small scales. lt is exclusively intended for the ULTRAPHOTcamera microscope and can only be used for transmitted lighi in conjunctionwith the macro-stage47 2561. When pleaseindicatethe orderingthe macro-stage, serialnumberof vour ULTRAPHOT.

71 Epi-LUMINARS These are intendedfor photographywith w i t h o u ti r i s d i a p h r a g mw i t h f i e l d t e n s our ULTRAPHOTcamera microscopeusing r e f l e c t e d - l i g hbt r i g h t - f i e l di l l u m i n a t i o n .T h e objectives 462542/43/45 can also be used o n o u r U N I V E R S A Lm i c r o s c o p e .

Table26

Designation

20 mm Epi-LUMINAR

Focal length mm

C a t a l o gN o tor objective

18.7

462542

l \ 4 a gn i f i c a t i o n s to be achieved with ULTRAPHOT

Catalog No. for macroilluminator

4 4 . 5 : 1 - 6 1: 1

47 2575

35:1-49:1

25 mm Epi-LUMINAR

25.0

4625 43

33:1-46:1

47 2575

27:'l-36:1

40 mm Epi-LUMINAR

40.0

4625 45

22:1-29:1

47 2575

1 7: 1 - 2 3 : 1

63 mm Epi-LUMINAR '100 mm Eoi-LUMINAR

63.4

4 62 5 1 7

102.3

462529

12:1-17.5:1

47 2576

8 . 5 : '-1 1 2 : 1

4 72 5 7 7

'10:1-14:1

6.5:1-9:1 T h e m a g n i f i c a t i o n s i n s m a l l p r i n t c a n b e a c h i e v e d b y u s i n g t h e O . 8 xa u x i l i a r y s y s t e m ( 4 6 2 s 8 0 ) w i t h t h e E p i - L U M I N A R S

ZEISSeyepieces

72

For tubes with an inside diameter of 23.2 mm; adapted to a location of the real intermediateimage 10 mm below the tube edge; with compensatingeffect adapted to the correctionof our objectives. C-type eyepiecesmay be used in conjunction with simple types of objective. Objectives of higher correctionshould, if possible, always be combined with Kpl eyepieces. This applies above all to the Planachromatsand Planapochromats.

Table 27

D e s gi n a t i o n

5x compensatingeyepiece 6.3xcompensatingeyepiece 8x compensatingeyepiece 10x compensatingeyepiece 12.5xcompensatingeyepiece 8x Kpl eyepiece 10x Kpl eyepiece 16x Kpl eyepiece 20x Kpl eyepiece 25x Kpl eyepiece 16x Kpl wide-angleeyepiece

Eyepiece magnrfication

Focal Iength mm

Fieldof-view number

5x 6.3x

50.5 39.9

8x 10x 12.5x

31.2

20 18 16 16 12.5 18 16

reIief mm

24.9

20.0

8x 10x 16x

20x 25x 16x

31.5

25.0 11 8.5 6.5 12

15.6 12.5 10.0 15.6

10

Ang le of view

Catalog No.

23"

463710 463810 463910 4 64 0 1 0 46 41 10

26" 300 360 360

33 360

36" 360

6.3 16

360

55"

463920 46 4020 46 4220 46 4320 46 4420 46 4244

73 Eyepiecesfor spectaclewearers

These have a particularlylong eye relief and are thereforesuitablefor wearersof eyeglasses.lt should be noted,however,that the spectaclelens also has an influenceon the h e i g h to f t h e e x i t p u p i l . M i n u sl e n s e sm a g n i fy, plus lenses reduce the image according to their power.A wearerof strongplus lenses may thereforebe unableevenwith theseeyepiecesto approachthe pupil of his eye close enoughto the eyepiecefor it to coincidewith the exit pupil of the latter.

Table 28

D e si g n a t i o n

8x Br Kpl eyepiece 12.5xBr Kpl eyepiece 10x Br Kpl wide-angleeyepiece 12.5xBr Kpl wide-angleeyepiece

Eyepiece magnification

8x

Eye relief mm

Focal Ie n g t h mm

Fieldof-view number

31.3

18 12.5 18 18

12.5x

17 16

10x

20

19.8 25.1

12.5x

15

20.3

Eyepiece is supplied with foldable rubber eyecup.

Angle of view

Catalog No.

32"

463922 464120 46 40 42464142.

360

41"

50"

74 Eyepiecesfor micrometerdisks

In these eyepieces,the mount of the collective lens is designedto hold micrometer disks. The disk is pressedagainst the eyep i e c e d i a p h r a g mb y m e a n so f a c l i p - o nr i n g so that it rests in the image plane. The eyepiece may also be used, with or without a m i c r o m e t e dr i s k , c o m b i n e dw i t h a n o r d i n a r y eyepieceof the same specification(table 27) i n a b i n o c u l a rb o d y .

Table29

Designation

8x compensatingeyepiece f o r 1 7 m m d i a . m i c r o m e t edr i s k s 12.5xcompensatingeyepiece t o r 1 7 m m d i a . m i c r o m e t edr i s k s 8x Kpl eyepiece f o r 1 7 m m d i a . m i c r o m e t edr i s k s

12.5xBr Kpl eyepiece f o r 1 7m md i a .m i c r o m e t edri s k s 16x Kpl eyepiece f o r 1 7 m m d i a . m i c r o m e t edr i s k s 20x Kpl eyepiece f o r 1 7 m m d i a . m i c r o m e t edr i s k s 10x Br Kpl wide-angleeyepiece f o r 1 9 m m d i a . m i c r o m e t edr i s k s 1 0 x B r K p l w i d e - a n g l ee y e p i e c ef o r 1 9 m m d i a . m i c r o m e t edr i s k sw i t h o r i e n t i n gs c r e w Eyepiece is supplied with foldable rubber eyecup.

trv6hi6^a

tr\,A

magnification

relief mm

8x 12.5x

8x

Focal length mm

Fieldof-view number

Angle of view

Catalog No.

31.2 1 6

300

46 49 13

20.0 12.5

360

46 41 13

31.5 1 8

330

463923

12.5x

to

19.8 12.5

360

46 41 23

16x

11

15.6 1 0

360

464223

Iz . c

360

46 4323

2Ox

8.5

10x

20

25.1

Itt

41"

464043.

10x

20

25.1

18

44"

464046

75 Micrometer disks

The following micrometerdisks with diameter 17 or 19 mm to be used in the eyepieces listed on table 29. The eyepiecesfor the stereomicroscopes listed in table 32 requiremicrometerdisks of 22.5mm diameter.

Catalog No.

- _

0

-: 1_--

2:

=:

"

1 0 m m e y e p i e c em i c r o m e t e rw, i t h 1 0 0d i v i s i o n s , 1 7m m d i a . Sameas above,but with 19 mm dia. Sameas abovefor stereomicroscopes

4 74 01 1 47 4002 47 4061

5 m m m i c r o r n e t edri s k ,w i t h 1 0 0d i v i s i o n s1, 7 m m d i a .

47 4010

t

10 mm contrastmicrometerdisk,with 100or 200divisions, 1 7m m d i a . 47 40 12 l -

1 0 m m l i n e c o n t r a s tm i c r o m e t edr i s k ,w i t h 1 0 0d i v i s i o n s , 1 7m m d i a . 47 4O1g

T h e s h a d e da r e at r a n s m i t s5 t o 1 0 % o f t h e i n c i d e n tl i g h t .

/

/# Hj+:Fi+r]]1]]]+|

/ f f i \

\|]:I]:I]:l]:1ffi/ \I]:]]]:r]:]]:llffi/

\--/

\

N e t m i c r o m e t edr i s k 1 0 x 1 0m m , 2 O x 2 0s q u a r e s , 1 7m m d i a . S a m ea s a b o v e ,b u t w i t h 1 9 m m d i a . Sameas abovefor stereomicroscopes

47 4014 47 40 44 47 4062

76 Catalog No.

r[-_l)

N e tm i c r o m e t edri s k5 x 5 m m ,1 0 x 1 0s q u a r e s , 1 7m md i a .

47 40 15

C r o s s h a idr i s k ,1 7 m m d i a . Sameas abovefor stereomicroscopes

47 4016 47 4060

1 0m m c r o s s h a im r i c r o m e t edr i s k ,w i t h 1 0 0d i v i s i o n s ' 1 9m m d i a .

474007

Reticulefor color televisionmicroscope, 1 9m m d i a .

47 4009

\"/

[--l t - l

47 4032 Reticulocytedisk this thrombocytes*, To simplifythe countingof reticulocytesand m i c r o m e t e rd i s k c o n t a i n sa s m a l l s q u a r ew i t h i n a l a r g e s q u a r e ( 8 x 8 m m , 1 1 . 2m m d i a g o n a l ) T . h e a r e a so f t h e t w o s q u a r e sa r e i n a r a t i oo f 1 0 : 1 . T h e n u m b e ro f r e t i c u l o c y t eisn t h e l a r g es q u a r ei s determinedin relation to that of the erythrocytesin the small square. This disk is preferablyused in the eyepieceswith focusing eye lens,Sx Kpl (463923)and 12.5xBr Kpl (464123). Object marker with diamond tiP

462960

This is screwed into the microscopelike an objective. The diameterof the circle to be made aroundthe object can be set on a graduation. Then the diamond tip is lowered onto the cover g l a s sa n d t h e c i r c l ee n g r a v e db y t u r n i n ga r i n g . B r e c h e ra n d S c h n e i d e r m a nTnh, eA m e r i c a nJ o u r n a lo f C l i n i c a lP a t h o l o g y , 2 01,0 7 9 - 1 0 8(31 9 5 0 )

77 Catalog No.

Stage micrometers

[1

A glass plate in a metal slide is provided w i t h a 5 m r n s c a l edivided into 5 intervals. A further distance of 1 mm is divided into 100/10m 0 m : 10p.

For transmittedlight: positivestage microme t e r 5 * 1 0 0 / 1 0 0m m , i n c a s e 47 4020 For rellected light: stage micrometer as above,but without cover glass 47 4022 For ultravioletmicroscopy:stage micrometer with slide and cover glass made of quartz glass 47 4023

[n n=) 0

For transmittedlight: negativestage micrometer 5*100/100 mm, in case 47 4021

5 4 3 2 r 0 , , ' , l , , , r l r , , rll,,r, ,rr, ]l r rl r lr,lrrrr rl r l r rlr r l I

t

5

t

l

Objectfinder

For stereomicroscopes: stage micrometer 25+50/10mm, in case 47 4025

462965

To allow the accurate relocation of object details, three squares marked ABC, each containing30x30 smaller squares, are engravedon a 26x76 mm slide. The 0.75x0.75mm squares are figuredfrom 1 to 900 and furthersubdividedinto 3x3 squares. The slide with the specimenneed only be exchangedfor the object f inderto give an accuratereadingof the positionof the stage.

7B Pointereyepieces

These eyepieces have a pointer in the imaEeplane,the tip of which can be moved t o a n y p o i n ti n t h e f i e l db y t u r n i n ga k n o ba n d rotatingthe eyepiecein the tube. For use in b i n o c u l a br o d i e st,h e p o i n t e re y e p i e c es h o u l d be paired with an ordinary eyepiece of the same opticaldaia, as listedinIable2T.

Table30

Designation

Eyepiece magnification

Bx compensatingeyepiecewith pointer 8x 12.5xBr Kpl eyepiecewith pointer 12,5x

r e lie f mm

Focal Ie n g t h mm

Fieldof-view number

Angle of view

Catalog No.

16

31.2 19.8

16 12.5

300 36"

4 6 3 91 8 4641 28

79 POL crosshaireyepieces This eyepiece is inserted into the tube with focusingeye lens and correctlyoriented.The crosshairshave been orientingscrew centeredwith high accuracy. They mark the opticalaxis of the polarizingmicroscopeand the vibrationdirectionof polarizerand analyzerin their zero positions.They serveas an index for measuringazimuth angles by rotation of the stage. Crosshairmicrometersare also suitedfor lengthmeasurementsunder orthoscooicand conoscopicobservation.

Table 31

Designation

Bx Kpl crosshaireyepiecepOL 12.5xBr Kpl wide-angleeyepiece with crosshairmicrometer

Eyepiece magnilication

Eye relief mm

8x 12.5x

tc

Focal length mm

Fieldof-view n u mD e r

Angle of view

Catalog No.

31.5

18

330

463925

20.3

18

50

464145

80 Eyepiecesfor stereomicroscopes

These are eyepiecesspecially designed for an for use with our stereomicroscopes, inside tube diameter of 30 mm. They are adaptedtor a real intermediateimagelocated 10 mm below the tube edge and have no compensatingeffect.

Table 32

Designation

4x eyepiece 10x eyepiece Samefor micrometerdisks 25x eyepiece Samefor micrometerdisks 10x Br wide-angleeyepiece 16x Br wide-angleeyepiece

Focal length mm

Fieldof-view number

10

62.6

12

25

30 20

Eyepiece magnif i c a t io n

Eye relief mm

4x 10x

10

25x 10x 16x

18 15

Angle of view

Catalog No.

27

46 36 01. 46 40 0'1 46 4004 46 4401 46 4404 46 4002" 46 4202

43" cc-

25

25

5b-

15.6

16

bb-

. ) n o t f o r s t e r e o m i c r o s c o pleV

depth-measuringCatalog No. 464005, with integralindex for The10xstereoscopic eyeplece stereoscopicdepth measurementis identical in designto the 10x eyepiecefor micrometer disks. C l a m p i n gr i n g 4 6 4 9 1 2 s e r v e sf o r o r i e n tation of the eyepiece.

81 Microprojectioneyepieces Forthe recommendedprojectiond istance, Eyepieces of longfocallengthfor use the scale factor of all projectioneyepieces, in microprojection equipment i. e. the relationshipbetween their field-of-

Table33 Transfer factors F o c a ll e n g t ho f m i c r o p r o j e c t i o n C a m e r aI e n so f f o c a l l e n g t h eyepiece 1 0 0m m 1 2 5m m

1 2 5m m '100mm 80 mm 63 mm

0.8x 1x 1.25x 1.6x

1x

1 6 0m m

1.25x 1.6x

1.25x 1.6x

2x

2x

2.5x

Microprojectioneyepieces

view number and the diameter of the projected image,is identical. lt is 100. This means that all the eyepieces,which have a field-of-viewnumber of 20, will prod u c e a n i m a g e o l 2 m d i a m e t e ra t t h i s d i s tance. In exceptional cases, these eyepieces may also be used for visual observationif eyepiece magnificationsare requiredwhich are lowerthan thoseof the normaleyepieces. This is why the valuescorrespondingto eyepiece magnificationand eye relief are also indicated. The eyepiecesmay also be used t o a d v a n t a g ei f i n c i n e m i c r o g r a p hoyn 1 6 m m or 8 mm film the aerial image produced by the camera lens is to be transferredto the film plane by the eyepiecewith litile or no magnification.In this case the camera.with a lens of suitable focal length, should be arranged above the eyepiece. The camera Iens may be a simple achromaticlens (telescope objective).Table 33 givesthe transfer factors which can be achieved,for example, with telescopeobjectivesand the four microprojectioneyepieces. For detailson microprojectionequipment includingprojectivessee brochure41-480.

Table 34

D e s i gn a t jo n

Eyepiece magnification

Eye relief mm

Focal Iength mm

125 mm microprojectioneyepiece 100 mm microprojectioneyepiece 80 mm microprojectioneyepiece 63 mm microprojectioneyepiece

2x

2.5x 3.2x 4x

30 30 30

126.0 20 100.0 20

30

75.3 63.1

Fieldof-view number

20 20

Recom_ mended for projection distance of m

Catalog No.

12.5

463379 463479 463579 463679

10 8

6.3

cial- urposee epteces 82 Screw micrometereyepiecesare usedfor Screwmicrometereyepieces with innerreading measuringobject lengths. The microscopist may now read the measuredvalue off the with an accuracy micrometer,measurements eyepiece. Thus, inner reading of measured values avoids mistakes caused by accommodation. After calibrating with the stage with an accuracy micrometer,measurements of 1/rooo of a millimetercan be made.

Table35 Screw micrometereyepieceswith inner reading for standardmonoculartube with 25 mm outsidediameter a n d f o r p o l a r i z i n gt u b e for tubeswith 33 mm diameter,for stereomicroscopes

with Kpl 8x Catalog No.

with Kpl 16x Catalog No.

463973 46 39 83

46 4273 46 4283

B3 Catalog No

K 8x goniometereyepiece for standardmonoculartube with 25 mm outsidediameter 46 39 74 for tube with 33 mm diameter, for stereomicroscopes 46 39 84 f o r p o l a r i z i n gt u b e 46 39 94 This eyepieceis providedwith crosshairswhich can be rotated through360oaboutthe intersectionof the two hairs. The angle of rotationcan be read off a graduationwith vernierto within 1/.roo.The eyepiece is intendedfor measuring angles in the microscopefield of view. K 8x and K 16x eyepiecesfor MicrohardnessTester 469977 with focusing eye lens This is a special eyepiecefor evaluatingthe Vickersindentations produced by means of a MicrohardnessTester. lt containstwo micrometerdiskswith rectangularpatternsof dashed lines which combineto form a crosshairin zero position. The two diskscan be symmetricallyshiftedin relationto the vertical centerline by meansof a knob. The diagonalof the indentation is measuredby this shift. The eyepieceis of the interiorreading type.

K 10xUVprojective 46 4082 This system is designed to produce a second real image e. g. on a Iight-sensiiive emulsion (photomicrography) or in a photometersystem(Type05 UV-microscopephotometer).

8x Kpl countingeyepiece 46 39 71 This eyepiececan be clamped in the monoculartube. lt corrtains two diaphragm blades with rectangularcutouts,which can be shifted symmetricallyin relationto the vertical center line,thus makingit possibleto selectsquaresectionsfrom the field of view. When using an object chamberof known depth, volumescan thus be easily limitedfor counting purposes. In other words, the eyepiece is intendedfor counting particles within a certainvolume.

B4 Catalog No.

46 39 70 8x Kpl eyepiecewilh adjustablecounting lines This has primarilybeen developedfor countingplanktonsamples. However,it may also be usedto advantagefor evaluating o t h e rs a m p l e s .l t i s c l a m p e di n a m o n o c u l a tru b e a n d c o n t a i n s a fixed horizontalhair and two vertical hairs which can be shiftedsymmetricallyin relationto the vertical center line by means of a knurled ring. The two adjustablehairs serve to delimit counting areas of any desiredsize.

10xBr K eyepiecefor spectaclewearers, for micrometer-disk turret for standardmonoculartube 46 4075 with 25 mm outsidediameter 46 40 95 f o r p o l a r i z i n gt u b e This eyepieceacceptsrevolvingdisks which servefor the convenientdispositionand rapid exchangeof severalmicrometer disks in the intermediateimage plane. This may be of advantagefor evaluatingclustersof particlesin connectionwith standardseries,for measuringparticle size and determining volume. Eachturret containseitherone revolvingdisk or two, arranged one abovethe other,with 6 or'12reticules,respectively.In anotherposition,the light passesfreely throughthe disks.

Type'a' "honeycomb net" micrometer-disklurret 47 4120 The micrometerdisks built into this double turret conform to ASTM E 19-46. The 11 disks correspondto the ASTM numbers 0 to 10. With the aid of the appropriaieobjectives,the A S T M n u m b e r s2 t o l Z c a n t h u s b e c o v e r e d .T h e h o n e y c o m b nets are extremely convenientfor estimating particle sizes with relativeradii of l/21 and 2:1. One opening contains a micrometerdisk with 10 mm/100 mm and 4 inch/128 graduations.

B5 Catalog No.

Type'b' "austenite-ferrite"micrometer-diskturret 47 41 21 Each of the two revolvingdisks holds six micrometerdisks with austenite-ferrite grain sizes in a ratio of 1:1 conforming to the Steel and lron Standard 1510-6'1.The disks bear the data for the Steel and lron Test Nos. 2 to 7. In conjunction with our EPIPLANobjectivesit is thus possibleto cover the n u m b e r s0 t o g . The micrometer-disk turrets47 4121 and 474122 togethergive the overallrequirementsof the Steeland lron Standard1510-61 and shouldthereforebe orderedand treatedas one unit.

Type 'c' micrometer-diskturret, 47 41 22 "ferritegrain sizes2:1 and 4:1" This double turret is identicalin design to the turret 474121, with the only differencethat it coversthe grain size ratios2:1 a n d4 : 1 . This micrometer-disk turret reflectsall the differentconditions of the Steel and lron Standard1510-61in conjunctionwith the turreI4T4121.The two shouldthereforebe orderedand treated as one unit.

Type'd' micrometer-disk turret, "ASTM-E112untwinnedgrainsn,

47 41 23

On this turret the grain-sizesamplesare arrangedaccording to ASTM-E 112 with the whole numbers 0-4 or, respectively, 7 and 8 as well as the half numbers4.5-5.5. Variationof the initial magnificationsof the objectivesthus allows the ASTM numbers2 to 10 to be covered. The distributionof grain sizes has been particularlyadaptedfor the assessmentof austenite grain sizes,but it may also be used in conjunctionwith isometric grain-sizesystems.

B6 Catalog No.

turret Integratingmicrometer-disk

6.-*'*'i?}:o'"o}

1

2

3

1

5

6

7

8

9

1

0

47 41 30 place integrating eyethe well-proved the of This turret takes piece L With this turret, sets of points arranged in a square are superimposedon the aerial microscopicimage according to the principleof point analysis. Any overlappingof a point with a componentis countedas a hit. The ratio of the number of hits to the total number of points gives the partial volume o r t h ep e r c e n t a g e b y v o l u m e . The revolvingdisk has sevenopenings.For optimumgeometric adaptationto the object, integratingdisks are mountedin four of these openings. The disks have the same base length and 25, 100,400and 900 points,respectively.In addition,the large clusters of points are centrally subdivided into 25, 100 and 400 pointsso that small object fields can be uniformlycounted with these partialnets. lf the coordinatemotionsof the attachable mechanicalstages are made parallelto the sides of the countingnets,then the specimenscan be completelycovered with the point nets.

Disks 5 and 6 of the turret are intendedfor the determination of grain sizes,shape factors, specific surfaces,diametersof medium-sizedparticlesaccordingto the diametermethod,and determinationof medium-sizedareas according to the circle method. With the disk 5, the radius quotientsof successive circles behave,according to internationalpractice,as 1/2:1, i. e. the quotientsof the secondfollowingradii are in the ratio 2 : 1 . T h e r a d i i o f t h e g r a i n - s i z ed i s k 6 a r e s e l e c t e di n l i n e a r , decimalorder in steps of ten. ln addition,the radii of the Aterberg divisioncustomaryin sedimeniarypetrography,2-6320-63, have been included. The seventhdisk, finally,is provided with crosshairsfor quantitativemicroscopy. Catalog No K 8x double eyepiecewith pointer for standardmonoculartube 46 49 20 with 25 mm outsidediameter for tube with 33 mm diameter, 46 49 21 for stereomicroscopes 46 49 22 for polarizingtube This unit has two separateeyepiecesspaced approx. 380 mm.

87 Bestell-Nr.

Centeringtelescope 46 4820 This is a small telescopeinsertedinto the tube insteadof the eyepiece and serving for observationof the magnified exit pupil of the microscopeobjectiveas well as the aperturestop image appearingin it. This allows accurate checkingof the objectiveaperture.lt servesinsteadof a Bertrandlensto adjust t h e p h a s e - c o n t r a sat n n u l a r d i a p h r a g mo f t h e c o n d e n s e ri n relationto the phase annulus in the objective,or to observe interferencefigures. The centeringtelescopeis focusedby shiftingits eyepiece. Centeringtelescope with built-in 5:100 micrometerdisk e. g. for the measurementof interferenceangles.

46 4821

Klein magnifier 46 48 30 Clip-oneyepiecemagnifierdesignedto magnifythe exit pupil of the entire microscope. lt servesthe same purpose as the centeringtelescope.

Pupillaryspectroscope

47 4300

This low-powereyepiecewith focusingeye lensand an iris d i a p h r a g mf o r l i m i t i n gt h e f i e l do f v i e w i s c o m b i n e dw i t h a h a n d spectroscope.The slit of the spectroscopeis located in the p l a n e o f t h e e y e p i e c ee x i t p u p i l . W i t h t h e a i d o f t h e i r i s d i a phragmthe detail to be investigatedspectroscopically can be singledout and its characteristicabsorptionor emissionspectrum viewed in the spectroscope.The hand spectroscopepermits a wavelengthscale and, if desired,a comparisonspectrum, to be projectedinto the image. With the aid of a specialpurposecamerathe spectracan be photographically recorded.

88 Intermediate The total magnificationpower of a micromagnification-changing systems scope, calculated from the initial magnificationof the objectiveand of the eyepiece, can be varied by means of an optical lens system.

Table 36 Designation

Factor

Wide-fieldsystem

0.8x

for microscope

To be screwed into the body tube, used primarilywith the STANDARDK and R Wide-fieldchanger 0 . 8 x- 1 x STANDARDK and R, w i t h h o l d e rs c r e wi n l i m bt o o Magnificationchanger 1.6x-1x Same as for the wide{ield changer Magnificationchanger 2x-1x Same as for the wide-field changer OPTOVAR 1x-1.25x-1.6x-2x STANDARDR, WL, among others Widejield OPTOVAR 0.8x 1x 1.25x 1.6x STANDARDR, WL, among others O P T O V A Ro n t u b e h e a d 1 . 2 5 x - 1 . 6 x - 2 x UNIVERSAL

Catalog No.

47 3067

473068

473060 47 3065

473050 473070 47 16 45"

47 21 89" PHOTOMICROSCOPE. partorstand

O P T O V A Ro n t u b e h e a d . Wide-fieldOPTOVAR on tube head is obtained if the standardrevolving nosepieceis replacedby the nosepiecewith widef i e l ds y s t e m( 4 7 3 1 5 5 ) .

1.25x-1.6x-2x

0.8x-1x-1.25x

47 2645ULTRAPHOT P H O T O M I C R O S C O PUEN. I V E R S A L ULTRAPHOT

Condensers Z-typecondensers

Simplecondensers

B9 For the condensercarrier of our routine and researchmicroscopes,parfocalizedfor a distanceof 38.2 mm, with built-inaperture i r i s d i a p h r a g mf o r b r i g h tf i e l d .

Table37 F^^rl

nhi6^+

distance* mm

Designation

Front lens

N.A.

length mm

Condenser.0.6 N.A..SZ Condenser,0.9 N.A.,Z with swing-outlens

fixed

0.6

24.8

s w i n g i n go u t

0.9

13.1

2.0-2.2

46 5252

swinging out

1.3 0.9

8.4 13.1

1 . 6- 1 . 8 2.0-22

465253 46 5262

1.3

8.4

1.6- 1.8

46 5263

0.9

13.1

2.0-22

46 5270

0.9

13.1

2.0-22

46 5282

C o n d e n s e1r . 3N . A .Z. w i t hs w i n g - o ul e t ns

Condenser,0.9 N.A.,Z. POL s w i n g i n go u t C o n d e n s e r1, . 3N . A . ,Z , P O L with swing-outlens s w i n g i n go u t Phase-contrast condenserll Z with swing-outlens s w i n g i n go u t Phase-contrast condenserllZ, POL with swing-outlens swingingout

Catalog No.

46 5200

. T h e o b j e c t d i s t a n c e i n d i c a t e st h e p o s i t i o n o f t h e i m a g eo f a n i n f i n i t e l yd i s t a n tl a m p f i e l d s t o p a b o v et h e s t a g es u r f a c ei n g l a s s t o r a m e d i u ma p e r t u r ea n d a c o n d e n s e r a c k e du p t o i t s u p p e r s t o p . T h i s m e a s u r ei s a n i n d i c a t i o no f t h e t h i c k n e s so f t h e o b j e c t sw h i c hc a n s t i l l b e p r o p e r l yi l l u m i n a t e dw i t h t h e c o n d e n s e rf o l l o w i n gK o h l e r ' sm e t h o d .

90 N.A.1.4 achromatic-aplanaticcondenserZ

Universal variable-focuscondenser for bright-fieldillumination,if used togetherwith the two auxiliaryfront lensesof N.A.0.6 and N.A.0.9.

ffi@ Table38 Focal length mm

Objectdistance mm

F r o n tl e n s

N.A.

lmmersed

1.4

6.8

Withoutfrontlens Auxiliaryfrontlens 0.63

0.32

30_7

37

0.64 0.9

15.3 10.4

6.6 1.8

0.9

AcJrromatic-apIanatic phase-contrast condenserlY Zl7

1.3-1.5

Catalog No.

465257

465255 465256

Dry condenserof long objectivedistances wiih aperiure iris diaphragmfor bright field and three annulardiaphragmson a revolving objecdisk, matchedwith our phase-contrast tives, for phase-contrastobservationsof living objects in samplechambers.

Table39 N.A.

Focal length mm

Object distance in glass mm

Catalog No-

0.63

15.3

11

465272

91 Acfiromatic-aplanatic bright-field dark-field phase-contrastcondenser VZ 465277

&@

F o r b r i g h t - f i e l d t h i si s a v a r i a b l ec o n denserlike the N.A.1.4condenserZ, 465257. Forthe phase-contrast technique it may be used with the N.A. 1.4 front lens in conjunctionwith our Ph objectivesof 16x or higherpower. F o r d a r k - f i e l d w o r k ,t h e N . A .1 . 4 f r o n t lens of the condenser is immersed (object d i s t a n c ei n g l a s s1 . 1 - 1 . 3m m ) . l t s a p e r t u r ei s then 1.1-1.4, and it is suited for use in conjunctionwith N.A.0.65to 1.0objectives.Highpower oil immersion objectives must be e q u i p p e dw i t h a n i r i s d i a p h r a g m .

Achromatic-aplanaticphase-contrast This is the same condenseras 465277. ffuorescencecondenser 465278 However, in positions 2 and 3 of the revolving disk, which are marked in blue, it contains two additionalannular diaphragmsfor polarizedlight. In conjunctionwith the light regulator 477220 these permit a phasecontrastimageto be continuouslyconverted into a fluorescentimage.

@@ Achromatic-aplanaticphase-contrastand interference-contrastcondenser 465294

For phase-contrastilluminationthis condenser with strain-free mounted lenses is similarto the condenserlV Z, 465277. In the p o s i t i o n sl , l l , l l l a n d l V t h e r e v o l v i n gd i s k contains a double-prismquartz wedge and an aperturediaphragm. Used togetherwith Planachromats6.3x, 16x, 40x and 100x, a polarizer and an interference-contrastslide 47 4431 or 4744 33, this condenserwill give NOMARSKId ifferentialinterferencecontrast. A rotaryspecimenstagewill be found helpful for this type of work (booklet41-210).

92 The pancraticcondenseris based on the Pancratic 0.13.. .0.90N.A. 465290 idea that an additional optical system of condensor, Condenserhead,1.3N.A. 465291 c o n t i n u o u s lvya r i a b l ef o c a l l e n g t hs h o u l db e located betweenthe condensersystem and t h e c o n d e n s e rd i a p h r a g mt o i m a g e t h e d i a phragm in the focal plane of the condenser systemat a continuouslyvariablescale and thus to cause a continuouschange of aperture. Since such a system at the same time makesit possibleto imagethe apertureof the l a m pc o n d e n s e irn t h e s p e c i m e np l a n ei n t h e senseopposedto that of the changein image scale,the product of the field-of-viewdiameter and the apertureremainsconstant. lf all elementsare suitablymatched,the basic remethod quiremeno t f t h e K o h l e ri l l u m i n a t i o n can be satisfiedin a very neat manner with a m i n i m u mo f m a n i p u l a t i o n . Operationis limitedto adjustingthe condenser for the maximumapertureof the obj e c t i v eu s e d s i m p l y b y t u r n i n g a k n o b . F o r further simplification,three stops are provided for low-power, medium-power and high-powerobjectives.Reductionof the illuminating aperture to a value below that of the maximumapertureof the objectiveused for observationis achievedas usual by varying the aperturediaphragmlocatedin a special insert in the microscope base. lt is mounted so that it can be shifted laterally and rotatedand thus also allowsoblique illum i n a t i o no f a n y d e s i r e da z i m u t h . The pancraticcondensercan be used as dry condenserfor aperturesup to 0.9 or as immersioncondenser up to a maximum a p e r t u r eo f 1 . 3 . l t s e r v e st o i l l u m i n a t et h e fields and aperturesof all objectivesfrom 2.5x to 100x. The pancratic condenser can easily be usedfor phasecontrast. For this purpose,an a n n u l a rd i a p h r a g ms u p p l i e dw i t h t h e u n i t i s inserted at the plane of the aperture diaphragm. By varying the adjustmentof the

93 pancratic system,the image of the annular diaphragmin the focal plane of the phasecontrast objective can be perfecily matched to the size of the phase annulus there and centeredwith the aid of the diaphragmadjustment. N.A.0.6conoscopiccondenserUD 46 55 50

This condenser is specially adapted to the position of the object on the universal stage and servesfor optimum illuminationof the conoscopicinterferencepattern. In conjunction with hemisphereswith a refractive index of 1.555it acts with an apertureof 0.6. In air its object distanceis 17 mm. lts working distancefrom 1 mm thick specimenslides i s t h e n1 5 m m .

N.A.0.8achromaticULTRAFLUAR-condenser This condenser for work by ultraviolet with iris diaphragm 46SS57 light is corrected and parfocalizedlike an ULTRAFLUARobjective(see page 58). At a wavelength of 280 mp its focal length is 6.2 mm and its initial magnification29.5x. Althoughit is a dry condenser,it may also be immersedin the usual glycerin used in UV microscopy. This condenseris insertedinto the condenser carrier of our microscopesin conjunction with change ring 466258, intermediatering 46 29 90 and carrierZtor microscope objectives, 4655 45.

94

Table40

Dark-fieldcondensers

Designation

N,A,

Focal length mm

Object distance mm

For objectives of N.A-

Catalog No.

1. 1 - 1. 3 0 . 7 5- 1. 0 4 6 5 5 0 0 1. 2 - 1 . 4 5 . 9 , il U l t r a c o n d e n s e1r. 2 , . . . 1 . 4N . A . o 6 0.6 -0.75 46 55 05 Dry dark-fieldcondenser,0.8. . .0.95 N.A. 0.8-0.95 8.2 0.4 - 0.6 46 55 06 6.5 Dry dark{ield condenser,0.7. . . 0.85N.A. 0.7-0.85 8.5 For our microscopeswith centeringcarrier,each of thesecondensersmust be equippedwith 465542. a condenserholderZ, For insertioninto a condensersleeve, 4655 41, the ultracondensermust be equippedwith the centerablecondenserholder S 46 55 40. the other condenserswith the condenserholderS

95 Spectacle-lenscondensers

For photomacrographywith LUMINARS (table25),for photographyby polarizedlight as POLmodels.

Table41

For LUMINAR

1 6m m 25 mm 40 mm 6 3 o r 1 0 0m m 1 0 0m m

Spectaclelens condenser

1* 2*

3* 4

Focal length mm

Diameter of clip-on diaphragm rmml

Catalog No.

POL model Catalog No.

21 3 4 82 137

3.5 6 9 15 27

46 55 61 465562 465563 465564 465565

465571 465572 465573 465574 465575

6 7

* For insertion into the centering carrier of our microscopes each oi these condensers must be equipped with condenser holder Z, 4655 42.

96 l l w i t h i n t e g r a l ,f u l l y a u t o m a t i c3 5 m m c a m e r a i n c l u d i n g p h o t o m u l t i p l i e r ; PHOTOMICROSCOPE e q u i p p e d f o r d i f f e r e n t i a l i n t e r f e r e n c e - c o n t r a s ti n t r a n s m i t t e d l i g h t , p h a s e c o n t r a s t a n d b r i g h l f i e l d

5.

97 U L T R A P H O lTl l C a m e r aM i c r o s c o p et o r 4 " x 5 " o r 3 5 m m p h o t o g r a p h y w i t h f u l l y a u t o m a t i c i,n t e g r a lc a m e r a i n c l u d i n gp h o t o m u l t i p l i e rT. h i s i n s t r u m e nct a n b e u s e dt c i ra t t i 6 c t i n i f i u e ia p p i i e o - i nm i c r o s c o p y .