LM - Microscope Eyepiece Reticle Basics

Created by Kathleen Patrick, Modified on Fri, 17 May at 4:53 PM by Kathleen Patrick

The terms ocular and eyepiece mean the same thing.


The terms reticle, reticule and graticule are used interchangeably by various organisation and countries, they all are referring to the same thing.


It is not normal to have a calibration certificate for an eyepiece reticle. The reason for this is that the reticle is installed in the eyepiece and all of the optics on the microscope can effect the size measured by the reticle. It is normal practice to use a stage micrometer to calibrate the complete microscope.


Size conversions and equivalents.


1mm = 1000µm1inch = 1000thou1mm = 39.4thou
0.1mm = 100µm0.1inch = 100thou1thou = 0.0254mm (25.4µm)
0.01mm = 10µm0.01inch = 10thou 
0.001mm = 1µm  


It is far better to increase the objective magnification than use a reticle with finer details. A recent example had a customer that wanted to have a reticle with a horizontal scale to measure spores of 2‐5µm in diameter. They said they normally used a 10x objective. We answered as follows;


'In this case, our NE1, which has a 10mm scale subdivided into 0.1mm divisions will measure 0‐1mm when used with a 10x objective lens. Each division will represent 0.01mm (10um). This will not be good enough to measure spores in the 2um ‐ 5um region. If you use a reticle with a smaller scale in the eyepiece it is very difficult to read so the answer is for the customer to use the 40x objective. Now the 10mm scale will measure 0‐0.25mm and each division will represent 2.5um. If the customer is able to use the 100x objective then the measurements can be even more accurate as each division will represent 1um'.


The diameter of the reticle is important to ensure it fits the eyepiece you have.

When we select an eyepiece reticle we are only concerned with the objective magnification. The mathematics of microscope magnification is very simple ‐ all you do is divide the size of the feature on the reticle by the objective magnification to get the size that it will actually measure at the stage.


Eg. a 10mm length scale when used with a 10x objective will measure 1mm at the stage. The same 10mm length reticle when used with a 40x objective will measure 0.25mm (250µm at the stage).


If you want to look at another way, if you have a 10µm at the stage and are using a 40x objective lens this will be magnified to 400µm (0.4mm) at the reticle image plan. The next section gives more sizing information.The eyepiece merely magnifies the image on the reticle.

Table Relating Stage Size and Objective Magnification with Size at Reticle Image Plane.

The two columns on the left hand side show the size of the specimen or feature at the stage. Along the top are typical objective magnifications. So, if you want to measure something that is about 50µm using a 40x objective lens this will actually be 2mm at the reticle image plane. A reticle with a 10mm scale in 0.1mm divisions (Our NE1) or one with a 5mm scale in 0.05mm divisions (Our NE5) may be suitable.


Measurement at StageMeasurement at Stage1X1.25X2X5X10X20X40X100X
1m0.001mm1m1.25m2m5m10m20m40m100m
5m0.005mm5m6m10m25m50m100m200m500m
10m0.010mm10m12.5m20m50m100m200m400m1mm
20m0.020mm20m25m40m100m200m400m800m2mm
50m0.050mm50m60m100m250m500m1mm2mm5mm
100m0.1mm100m125m200m500m1mm2mm4mm10mm
200m0.2mm200m250m400m1000m2mm4mm8mm20mm
500m0.5mm500m600m1mm2.5mm5mm10mm20mm50mm
1000m1mm1mm1.25mm2mm5mm10mm20mm40mm100mm
10 000m10mm10mm12.5mm20mm50mm100mm200mm400mm1000mm


Colour of reticle lines does not matter in a microscope eyepiece. All lines, whatever their colour, block the light from the specimen/stage so the pattern will always appear dark against a brighter background.


Reticle Diameters for Common Microscopes

Pyser‐SGI has compiled a list of eyepieces and microscope types from the major microscope manufacturers and listed alongside them the reticle sizes that fit them. Most of these eyepieces have some means of securing the reticle in position ‐ always best to just check first before ordering the reticle. Pyser offer a supply and fit service if you have any doubts.


BrandEyepieceReticle DiameterModel
NIKONC‐W 10xB/2225mm 
 C‐W 15x/1619mm 
 C‐W 20x19mm 
 CFI 10x CFI 12.5x CFI 1527mm 
 CFI UW 10x27mm 
 CFUW1027mm 
 CFW 10x CFW 15x21mm 
 CFWN 10x CFWN 15x21mm 
 E1‐CFI 10x E2‐CFI 10x E2‐CFI 15x27mm 
 L‐W10x ESD (FOV 22)25mmEclipse LV150L
 SME 10x /2327mm 
 SME 15x~ 
 SME 20x16mm 
 SME 10x /2127mmSMZ‐10
 SMZ U UW10x A/2425mmSMZ‐U
 SMZ U UW15x25mmSMZ‐U
 SMZ U UW20x21mmSMZ‐U
 SMZ U UW30xn/pSMZ‐U
 SMZ 10 E10xA24mmSMZ‐10
 SMZ 10 UW15x /1727mmSMZ‐10
 SMZ 10 UW20xn/pSMZ‐10
BrandEyepieceReticle DiameterModel
OLYMPUSWHN10X / WHN10X ‐H24mmBX61 / BX51 / BX41
 WH10X / WH10X ‐H / WH15X24mmBX50 / BX40
 WHS10X‐H / WHS15X‐H24mmSZX7 / SZX9 / SZX12
 WHSZ10X‐H / WHSZ15X‐H24mmSZ61
 WHSZ20X‐H / WHSZ30X‐H24mmSZ61
 CWH10X / CWH10X‐H24mmCX41
 GSWH10X / GSWH10X‐H24mmSZ60 / SZ40 / SZ11 / SD / SF
 GSWH15X / GSWH15X‐H24mmSZ60 / SZ40 / SZ11 / SD / SF
 GW10X / GWH10X24mmSZ60 / SZ40 / SZ11 / SD / SF
 WH12.5X / WH12.5X ‐H24mm 
 GWH10X‐D26mmSZH / SZH10
 SWHK10X28mmVANOX, and other
 G10X / G15X22mm 
 WHK10X / WHK15X / NWHK10X20.4mm20mm loose fitting alternative
 (*WHK10X‐H canonot be installed)  
 NFK 2.5X/ 3.3X/ 5X/ 6.7X20.4mm20mm loose fitting alternative
 PE 2X/2.5X/ 3.3X/ 4X/ 5X20.4mm20mm loose fitting alternative
 GX‐SLM Scale Slider25.5mmSpecial 3.8mm thick
 CWHK10X / NCWHK10X /G20X19mmCK40 / CK30 / CH40 / CH30 / CH2
BrandEyepieceReticle DiameterModel
LEICA11507808 (S10x/25Br.M)26mmDMR, DMIR, DML
 11507807 (S10x/22B.M)26mmDMR, DMIR, DML
 11507801 (10x/20Br.M)26mmDMR, DMIR, DML
 11507802 (10x/20Br.M)26mmDMR, DMIR, DML
 11506515 (12.5x/16Br.M)26mmDMR, DMIR, DML
 10447160 (10x/21B)23mmMX series / Z series
 10445301 (16x/14B)23mmMX series / Z series
 10445302 (25x/9.5B)23mmMX series / Z series
 10445303 (40x/6B)23mmMX series / Z series
 10450023 (10x/23B)24.5mmM205C / M165C
 10450024 (16x /15B)24.5mmM205C / M165C
 10450025 (25x/9.5B)24.5mmM205C / M165C
 10450026 (40x/6B)24.5mmM205C / M165C
 10 446 333 (10x/23,adjustable)24.5mmDM750 / S6 Series / S8APO
 10 446 355 (16x/16,adjustable)24.5mmS6 Series / S8APO
 10 446 357 (20x/12,adjustable)24.5mmS6 Series / S8APO
 10 446 329 (10x/23B,adjust.f/eyeglasses)24.5mmS6 Series / S8APO
 10 447 131 (10x/23,adjustable)24.5mmS6 Series / S8APO
 10 447 133 (16x/16,adjustable)24.5mmS6 Series / S8APO / EZ Series
 10 447 135 (20x/126,adjustable)24.5mmS6 Series / S8APO / EZ Series
 10 447 137 (for eyeglasses10x/23B,adjustable)24.5mmS6 Series?/S8APO
 10 447 139 (for eyeglasses16x/15B,adjustable)24.5mmS6 Series?/S8APO
 10 445 302 (25x/9.5B,adjust.f/eyeglasses)24.5mmS6 Series?/S8APO
 10 445 303 (40x/6B,adjust.f/eyeglasses)24.5mmS6 Series?/S8APO
 10 447 280 (10x/20B,adjust.f/eyeglasses)24.5mmEZ Series
 Leitz Wetzlar Periplan GF10x/1821mm 
BrandEyepieceReticle DiameterModel
ZEISSE‐PL 10x/20 Br. Foc26mm 
 PL 10x/21 Br foc26mm 
 PL 10x/23 Br. Foc26mm 
 WF 10x/1823mmPrimostar
 PL16x/16 Br. Foc21mm 
 W 25x/10 foc21mm 
 Kpl‐W 10x/18 [#46 40 43‐9902]21mm872e
BrandEyepieceReticle DiameterModel
MEIJI TECNOEM series 10x25mm 
 IM7000 series 10x25mm 
 ML2000 series 10x21mm 
 ML5000 series 10x21mm 
 ML7000 series 10x21mm 
 ML8000 series 10x21mm 
 ML8500 series 10x21mm 
 MT4000 series 10x21mm 
 MT5000 series 10x25mm 
 MT6000 series 10x25mm 
 MT9000 series 10x21mm 
 RZ series 10x25mm 
 RZ series 15x19mm 
 RZ series 20X19m 
 TC5000 seies 10x25mm 
 TM200 all series19mm 
 TM400 all series19mm 
BrandEyepieceReticle DiameterModel
MOTIC100FL 10x21mm 
 100FLA 10x21mm 
 100FLAQ 10x21mm 
 B1‐211 10x21mm 
 B1‐220 10x21mm 
 B1‐223 10x21mm 
 M Series 10x23mm 
 S‐10‐P 10x23mm 
 S‐20‐2L 10x23mm 
 SL‐40‐PB 10x23mm 
 SMZ‐140 10x23mm 
 SMZ‐143 10x23mm 
 ST‐30‐2L 10x23mm 
 ST‐39 10x23mm 
 10x24mmBA 210, BA 310
 10x24mmAE 2000
BrandEyepieceReticle DiameterModel
LABOMEDPrefix 512, 312 or 91321mm 
 Prefix 912, 414, 914 or 61226mm 
 Prefix 123, 125 or 12728mm 
Brand
Bausch Lomb, Cambridge Inst.The following list shows the Bausch & Lomb reticle part number with the Pyser equivalent or nearest match. All reticles are specified as 21mm diameter.
 Part NumberDescriptionProSciTech Part NumberPyser Description
 31‐16‐01Scale 5mm in 0.05mmPYS01B21203NE5 Eyepiece Reticle, 5mm in 0.05mm divisions
 31‐16‐02Scale 10mm in 0.1mm.PYS01B21201NE1 Eyepiece Reticle, 10mmin 0.1mm divisions
 31‐16‐04Scaled to measure 0.001"Would be made to special order with calibration factor
 31‐16‐05Scale 5mm in 0.05mmPYS01B21203NE5 Eyepiece Reticle, 5mm in 0.05mm divisions
 31‐16‐07Each least division 0.005mm @ 1x objective powerPYS01B21219NE31 Eyepiece Reticle
 31‐16‐08Scaled to measure 0.001" at 3x magWould be made to special order with calibration factor
 31‐16‐09Micro DiscWould need image information to match pattern
 31‐16‐110.5mm squaresPYS01B21208OR01B21207NE10A Eyepiece Reticle, 10 x 10 grid of 0.5mm squares, indexed or NE10 Eyepiece Reticle, net grid of 0.5mm squares
 31‐16‐121mm squaresPYS01B21210OR01B21209NE11A Eyepiece Reticle, 10 x 10 grid of 1mm squares, indexed or NE11 Eyepiece Reticle, net grid of 1mmsquares
 31‐16‐71100 x 1mm square gridPYS01B21210NE11A Eyepiece Reticle, 10 x 10 grid of 1mm squares, indexed
 31‐16‐30Crossline, 0.080mm line widthPYS01B21234NE81 Crossline Eyepiece Reticle, 0.040mm line width
 31‐16‐42Scaled to measure 0.001" at 3x magWould need image information to match pattern
 31‐16‐43100 divisions of 0.1mmPYS01B21021NE1 Eyepiece Reticle, 10mmin 0.1mm divisions
 31‐16‐44Scaled to measure 0.01mm at 7x magWould be made to special order with calibration factor
 31‐16‐45Grid of 64 squaresPYS01A21218NE29 Eyepiece Reticle, Whipple grid
 31‐16‐46Protractor reticle, 180 degPYS01B21216NE25 Eyepiece Reticle, half protractor
 31‐16‐47General purpose reticleWould need image information to match pattern
 31‐16‐87Stage micrometer ruled to 0.005"PYS02A00402S4 Stage Micrometer, 0.1" in 0.001" divisions
 31‐16‐89Stage micrometer ruled to 0.001"PYS02A00402S4 Stage Micrometer, 0.1" in 0.001" divisions
 31‐16‐90Stage micrometer ruled to 0.01mmPYS02A00404S8 Stage Micrometer, 1mm in 0.01mm divisions
 31‐16‐99Stage micrometer ruled to 0.01mmPYS02A00404S8 Stage Micrometer, 1mm in 0.01mm divisions
 31‐16‐35Micrometer scale 0.001"PYS01B21214NE20 Eyepiece Reticle, 0.1" in 0.001" divisions

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