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Leica S4E & S8APO

Author: Mitch Richling
Updated: 2025-12-11

Copyright 2026 Mitch Richling. All rights reserved.

Table of Contents

Check out my home page for more stuff: https://www.mitchr.me/

1. Introduction

This page contains my personal notes for the Leica S8APO & S4E stereo microscopes. Being my personal notes, the content here isn't terribly polished; however, I've gone ahead and published it anyhow in hope someone might find it useful.

2. Microscope Symbols & Formulas

2.1. Variables

Table 1: Symbols & Formulas
Variable Description Units Notes
\(S_{MAG}\) Magnification At Sensor Ratio  
\(S_{FOVh}\) Sensor Horizontal Field Of View mm  
\(S_{FOVv}\) Sensor Vertical Field Of View mm  
\(I_{SCLh}\) Image Horizontal Scale Pixel/mm  
\(I_{SCLv}\) Image Vertical Scale Pixel/mm  
\(S_w\) Sensor Physical Width mm  
\(S_h\) Sensor Physical Height mm  
\(S_d\) Sensor Physical Diagonal mm  
\(S_A\) Sensor Physical Area square mm  
\(I_w\) Image/Sensor Pixel Width pixel  
\(I_h\) Image/Sensor Pixel Height pixel  
\(I_{MP}\) Total number of Image/Sensor Pixels Megapixel  
\(L_s\) Length At Sensor mm  
\(L_o\) Object Length mm  
\(A\) Auxiliary Ratio  
\(Z\) Zoom Ratio  
\(O_c\) Camera Objective Ratio camera relay lens, camera port lens
\(O_d\) Camera Objective Image Circle Diameter mm  
\(P_w\) Sensor Pixel Width mm  
\(P_h\) Sensor Pixel Height mm  
\(P_{AR}\) Pixel Aspect Ratio Ratio  
\(V_{FOV}\) Visual Field Of View mm  
\(E_{FN}\) Eyepiece Field Number mm  
\(E_{MAG}\) Eyepiece magnification Ratio  
\(V_{MAG}\) Visual Magnification Ratio  
\(R_c\) Reticle Unit Conversion Factor mm/Ru \(1\,\mathrm{Ru}=1\,\mathrm{mmu}\) @ \(Z=1\) & \(A=1\)
\(R_s\) Reticle Scale mm/Ru  
\(L_R\) Length in Reticle Units Ru  
\(I_{AR}\) Image Aspect Ratio Ratio  
\(P_{IJSPAR}\) ImageJ Scale Pixel Aspect Ratio Ratio  
\(W\) Working Distance mm  
\(NA\) Numerical Aperture N/A  

2.2. Formulas

Image/Sensor magnification
\[S_{MAG} = \frac{L_s}{L_o} = A \cdot Z \cdot O_c\]
Image/Sensor Horizontal Field Of View
\[S_{FOVh} = \frac{\min(O_d, S_w)}{S_{MAG}}\]
Image/Sensor Vertical Field Of View
\[S_{FOVv} = \frac{\min(O_d, S_h)}{S_{MAG}}\]
Image/Sensor Horizontal Scale
\[I_{SCLh} = \frac{S_{MAG} \cdot I_w}{S_w} = \frac{S_{MAG}}{P_w}\]
Image/Sensor Vertical Scale
\[I_{SCLv} = \frac{S_{MAG} \cdot I_h}{S_h} = \frac{S_{MAG}}{P_h}\]
Visual magnification
\[V_{MAG} = A \cdot Z \cdot E_{MAG}\]
Visual Field Of View
\[V_{FOV} = \frac{E_{FN}}{A \cdot Z}\]
Reticle Scale
\[\frac{R_c}{Z \cdot A}\]
Reticle Length Measurements
\[\mathrm{Length}=R_s \cdot L_R\]
Sensor Diagonal length
\[S_d = \sqrt{S_w^2 + S_h^2}\]
Sensor Pixel Width
\[P_w = \frac{S_w}{I_w}\]
Sensor Pixel Height
\[P_h = \frac{S_h}{I_h}\]
Pixel Aspect Ratio
\[P_{AR} = \frac{P_w}{P_h} = \frac{S_w \cdot I_h}{I_w \cdot S_h}\]
Image Aspect Ratio
\[I_{AR} = \frac{I_w}{I_h}\]
ImageJ Scale Pixel Aspect Ratio
\[P_{IJSPAR} = \frac{1}{P_{AR}}\]

3. S4E

3.1. Magnification and FOV at Various Zoom Levels With 10x/23 Eyepiece

Table 2: S4E – Magnification and FOV at Various Zoom Levels With 10x/23 Eyepiece
  \(A=\) \(W=\) \(A=\) \(W=\) \(A=\) \(W=\) \(A=\) \(W=\) \(A=\) \(W=\)
  \(0.5\times\) \(200\,\mathrm{mm}\) \(0.75\times\) \(130\,\mathrm{mm}\) \(1.0\times\) \(110\,\mathrm{mm}\) \(1.6\times\) \(55\,\mathrm{mm}\) \(2.0\times\) \(35\,\mathrm{mm}\)
\(Z\) \(E_{MAG}\) \(V_{FOV}\) \(E_{MAG}\) \(V_{FOV}\) \(E_{MAG}\) \(V_{FOV}\) \(E_{MAG}\) \(V_{FOV}\) \(E_{MAG}\) \(V_{FOV}\)
0.63 3.15 73.02 4.72 48.68 6.30 36.51 10.08 22.82 12.60 18.25
0.80 4.00 57.50 6.00 38.33 8.00 28.75 12.80 17.97 16.00 14.38
1.00 5.00 46.00 7.50 30.67 10.00 23.00 16.00 14.38 20.00 11.50
1.25 6.25 36.80 9.38 24.53 12.50 18.40 20.00 11.50 25.00 9.20
1.60 8.00 28.75 12.00 19.17 16.00 14.38 25.60 8.98 32.00 7.19
2.00 10.00 23.00 15.00 15.33 20.00 11.50 32.00 7.19 40.00 5.75
2.50 12.50 18.40 18.75 12.27 25.00 9.20 40.00 5.75 50.00 4.60
3.00 15.00 15.33 22.50 10.22 30.00 7.67 48.00 4.79 60.00 3.83

3.2. Reticle Scale, Magnification, and FOV at Zoom Stops With 10x/23 Eyepiece

Table 3: S4E – Reticle Scale, Magnification, and FOV at Zoom Stops With 10x/23 Eyepiece
\(A\) \(Z\) \(E_{MAG}\) \(E_{FN}\) \(R_s\) \(V_{MAG}\) \(V_{FOV}\)
0.50 0.63 10 23 3.17460 3.15 73.02
0.50 3.00 10 23 0.66667 15.00 15.33
0.75 0.63 10 23 2.11640 4.72 48.68
0.75 3.00 10 23 0.44444 22.50 10.22
1.00 0.63 10 23 1.58730 6.30 36.51
1.00 3.00 10 23 0.33333 30.00 7.67
1.60 0.63 10 23 0.99206 10.08 22.82
1.60 3.00 10 23 0.20833 48.00 4.79
2.00 0.63 10 23 0.79365 12.60 18.25
2.00 3.00 10 23 0.16667 60.00 3.83

3.3. Auxiliary Len Magnification & Working Distance

Table 4: S4E – Auxiliary Lens Magnification, and Working Distance
\(A\) \(W\) Perf Part
\(0.32\times\) 300 mm Acro 10446316
\(0.5\times\) 200 mm Acro 10446318
\(0.63\times\) 155 mm Acro 10446319
\(0.75\times\) 130 mm Acro 10446320
\(1.6\times\) 55 mm Acro 10446321
\(2.0\times\) 35 mm Acro 10446322
\(0.3–0.4\times\) 200–350 mm Acro 10446325
\(0.6–0.75\times\) 77–137 mm Acro 10446323

4. S8APO

4.1. Magnification and FOV at Various Zoom Levels With 10x/23 Eyepiece

Table 5: S8APO – Magnification and FOV at Various Zoom Levels With 10x/23 Eyepiece
  \(A=\) \(W=\) \(A=\) \(W=\) \(A=\) \(W=\) \(A=\) \(W=\)
  \(0.32\times\) \(200\,\mathrm{mm}\) \(0.63\times\) \(101\,\mathrm{mm}\) \(1.0\times\) \(75\,\mathrm{mm}\) \(2.0\times\) \(25\,\mathrm{mm}\)
\(Z\) \(V_{MAG}\) \(V_{FOV}\) \(V_{MAG}\) \(V_{FOV}\) \(V_{MAG}\) \(V_{FOV}\) \(V_{MAG}\) \(V_{FOV}\)
1.0 3.2 71.88 6.30 36.51 10.0 23.00 20 11.50
1.25 4.0 57.50 7.88 29.21 12.5 18.40 25 9.20
1.6 5.1 44.92 10.08 22.82 16.0 14.38 32 7.19
2.0 6.4 35.94 12.60 18.25 20.0 11.50 40 5.75
2.5 8.0 28.75 15.75 14.60 25.0 9.20 50 4.60
3.2 10.2 22.46 20.16 11.41 32.0 7.19 64 3.59
4.0 12.8 17.97 25.20 9.13 40.0 5.75 80 2.88
5.0 16.0 14.38 31.50 7.30 50.0 4.60 100 2.30
6.3 20.2 11.41 39.69 5.79 63.0 3.65 126 1.83
8.0 25.6 8.98 50.40 4.56 80.0 2.88 160 1.44

4.2. Reticle Scale, Magnification, and FOV at Zoom Stops With 10x/23 Eyepiece

Table 6: S8APO – Reticle Scale, Magnification, and FOV at Zoom Stops With 10x/23 Eyepiece
\(A\) \(Z\) \(E_{MAG}\) \(E_{FN}\) \(R_s\) \(V_{MAG}\) \(V_{FOV}\)
0.32 1 10 23 3.12500 3.20 71.88
0.32 8 10 23 0.39062 25.60 8.98
0.63 1 10 23 1.58730 6.30 36.51
0.63 8 10 23 0.19841 50.40 4.56
1.00 1 10 23 1.00000 10.00 23.00
1.00 8 10 23 0.12500 80.00 2.88
2.00 1 10 23 0.50000 20.00 11.50
2.00 8 10 23 0.06250 160.00 1.44

4.3. Numerical Aperture With No Auxiliary Lens

Table 7: S8APO Numerical Aperture
Zoom Numerical Aperture
\(Z\) \(NA\)
1.0 0.026
1.25 0.031
1.6 0.038
2.0 0.046
2.5 0.056
3.2 0.069
4.0 0.081
5.0 0.093
6.3 0.100
8.0 0.100

4.4. Auxiliary Len Magnification & Working Distance

Table 8: S8API – Auxiliary Lens Magnification, and Working Distance
Leica Part # \(A\) \(W\) Perf
10446334 \(0.32\times\) 200 mm Achro
10446335 \(0.63\times\) 100 mm APO
10446336 \(1.6\times\) 37 mm APO
10446337 \(2.0\times\) 25 mm APO

4.5. Leica C-Mount Video Objective Data

Table 9: Leica C-Mount Video Objective Data
Leica Part # Leica Part Name Mag \(O_d\) Notes Ref
10445928 Leica Video Objective \(0.32\times\) 0.32 6.7 Estimated \(O_d\) co32
10450528 Leica Video Objective \(0.5\times\) 0.50 10.5 Measured \(O_d\) co50
10447367 Leica Video Objective \(0.63\times\) 0.63 13.2 Estimated \(O_d\) co63
10446307 Leica Video Objective \(0.8\times\) 0.80 16.8 Estimated \(O_d\) co80

Note the image circles are all the same size at the sensor for a particular video objective, but FOV will change with the auxiliary lens.

With \(O_d=0.5\times\) we can capture the full image circle with a Micro Four Thirds (Olympus OM-D E-M1 Mark II) sensor, but only about 37% of the image circle with an IMX477 (RPI HQ) sensor. Note that about 65% of the Micro Four Thirds sensor is outside the image circle – i.e. wasted pixels.

Table 10: Image Circles with \(O_d=0.5\times\)
  \(Z=1\) \(Z=8\)
\(A=0.63\) 10450528-10446335-z1_200.png 10450528-10446335-z8_200.png
\(A=1.00\) 10450528-NONE-z1_200.png 10450528-NONE-z8_200.png

With \(O_d=0.32\times\) the image circle shrinks, and now we can capture about 76% of the image circle with an IMX477 (RPI HQ); however, about 3% percent of the sensor is outside the image circle – i.e. wasted sensor pixels. Note that with the smaller image circle the Micro Four Thirds sensor is even less efficiently used with about 84% of the sensor pixels wasted.

Table 11: Image Circles with \(O_d=0.32\times\)
  \(Z=1\) \(Z=8\)
\(A=0.63\) 10445928-10446335-z1_200.png 10445928-10446335-z8_200.png
\(A=1.00\) 10445928-NONE-z1_200.png 10445928-NONE-z8_200.png

4.6. Attaching Cameras

The Leica documentation suggests using a chain of adapters for attaching a generic digital camera. The first part of the chain is one of the following three parts: 10447436 1.6× DSLR tube, 10446175 2.5× DSLR tube, or 10445930 1.0× video/photo objective. Next will be one or more adapters for your camera. The result can be a tower of adapters taller than your microscope! For cameras with large sensors, this really is the only way to go. An excellent write-up for this approach may be found here. A good discussion on MicrobeHunter.com may found here.

For cameras with Micro Four Thirds and smaller sensors, a simpler approach is connect your camera via a c-mount adapter to one of Leica's "C-Mount Video Objectives": 10445928 \(0.32\times\), 10450528 \(0.5\times\), 10447367 \(0.63\times\), or 10446307 \(0.8\times\). These adapters are intended to be used with Leica's microscope cameras, but they will work with any c-mount camera – including your SLR with a c-mount adapter.

With the \(0.5\times\) objective one will obtain a nice 10.5mm image circle which is just about perfect for whole field imaging with the 13mm tall sensor in a Micro Four Thirds camera.

I use two cameras with my S8APO:

4.7. Camera FOV & Image Scales

Table 12: Camera FOV & Image Scales
          RPI         OLY        
\(A\) \(Z\) \(O_c\) \(O_d\) \(S_{MAG}\) \(P_{IJSPAR}\) \(I_{SCLh}\) \(I_{SCLv}\) \(S_{FOVh}\) \(S_{FOVv}\) \(P_{IJSPAR}\) \(I_{SCLh}\) \(I_{SCLv}\) \(S_{FOVh}\) \(S_{FOVv}\)
0.63 1 0.50 10.5 0.32 1.0000000 203.23 203.23 19.96 14.96 0.9961686 93.85 94.21 33.33 33.33
0.63 8 0.50 10.5 2.52 1.0000000 1625.81 1625.81 2.49 1.87 0.9961686 750.79 753.67 4.17 4.17
1.00 1 0.50 10.5 0.50 1.0000000 322.58 322.58 12.57 9.42 0.9961686 148.97 149.54 21.00 21.00
1.00 8 0.50 10.5 4.00 1.0000000 2580.65 2580.65 1.57 1.18 0.9961686 1191.72 1196.31 2.62 2.62
2.00 1 0.50 10.5 1.00 1.0000000 645.16 645.16 6.29 4.71 0.9961686 297.93 299.08 10.50 10.50
2.00 8 0.50 10.5 8.00 1.0000000 5161.29 5161.29 0.79 0.59 0.9961686 2383.45 2392.62 1.31 1.31

5. S4 and S8 Magnification Coverage

Various magnifications may be reached with different combinations of eyepiece, power, & auxiliary lens.

Table 13: S4
   \(E_{MAG}\)       \(A\)           003   004   005   006   008   010   013   016   020   026   032   040   050   064   080   100   128   160   200   256   320   400   500   640 
   \(10\times\)    \(0.50\times\)
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(0.75\times\)
 
 
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   \(16\times\)    \(0.50\times\)
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(1.00\times\)
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
 
 
   \(25\times\)    \(0.50\times\)
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(1.60\times\)
 
 
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
   \(20\times\)    \(1.00\times\)
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(2.00\times\)
 
 
 
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
   \(16\times\)    \(1.60\times\)
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
 
   \(20\times\)    \(1.60\times\)
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
   \(25\times\)    \(1.60\times\)
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
   \(40\times\)    \(1.60\times\)
 
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
 
   \(40\times\)    \(2.00\times\)
 
 
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
 
 
 
 
Table 14: S8
   \(E_{MAG}\)       \(A\)           003   004   005   006   008   010   013   016   020   026   032   040   050   064   080   100   128   160   200   256   320   400   500   640 
   \(10\times\)    \(0.32\times\)
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(0.63\times\)
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
 
 
   \(10\times\)    \(1.00\times\)
 
 
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
 
 
   \(20\times\)    \(0.63\times\)
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-
 
 
 
 
 
 
 
 
   \(16\times\)    \(1.00\times\)
 
 
 
 
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
 
   \(10\times\)    \(2.00\times\)
 
 
 
 
 
 
 
 
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
 
 
 
 
 
 
   \(25\times\)    \(1.00\times\)
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-
 
 
 
 
 
   \(16\times\)    \(2.00\times\)
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-
 
 
 
 
   \(40\times\)    \(1.00\times\)
 
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-
 
 
 
   \(25\times\)    \(2.00\times\)
 
 
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-
 
 
   \(40\times\)    \(2.00\times\)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
-
-
-
-
-
-
-
-
-
-


Table 15: Colors
Color Meaning
 
 APO
 
 Acro


Table 16: Symbols
Symbol Meaning
- I don't have this combination of equipment
✓
 I have this combination of equipment

6. Reticle Unit Conversion Software For free42 and DM42

The computational part of this code is trivial. The value of the program really is in the settings menus – allowing the user to quickly change equipment settings and convert measurements.

The code as-is will work pretty well for people using an S8APO or S4E scope with a 10x EP and standard reticle; however, users with diffrent equipment will want to modify the settings menus.

6.1. The menu

Table 17: Application Menu
Key Without [SHIFT] With [SHIFT] Notes
A Store A Display A Stored in variable "mrcvA"
Z Store Z Display Z Stored in variable "mrcvZ"
Rc Store Rc Display Rc Stored in variable "mrcvRc"
▒▒▒▒      
▒▒▒▒      
CONV Convert from Reticle Units Convert from Reticle Units  
8;.32 Leica S8APO; Z=1.00x; A=0.32x aux Leica S8APO; Z=8.00x; A=0.32x aux  
8;.63 Leica S8APO; Z=1.00x; A=0.63x aux Leica S8APO; Z=8.00x; A=0.63x aux  
8;1 Leica S8APO; Z=1.00x; A=1.00x (no aux) Leica S8APO; Z=8.00x; A=1.00x (no aux)  
8;1.6 Leica S8APO; Z=1.00x; A=1.60x aux Leica S8APO; Z=8.00x; A=1.60x aux  
8;2 Leica S8APO; Z=1.00x; A=2.00x aux Leica S8APO; Z=8.00x; A=2.00x aux  
ZZZ Leica S8APO; Z=1.00x; A=NO CHANGE Leica S8APO; Z=8.00x; A=NO CHANGE  
4;.32 Leica S4; Z=0.63x; A=0.32x aux Leica S4; Z=3.00x; A=0.32x aux  
4;.5 Leica S4; Z=0.63x; A=0.50x aux Leica S4; Z=3.00x; A=0.50x aux  
4;.63 Leica S4; Z=0.63x; A=0.63x aux Leica S4; Z=3.00x; A=0.63x aux  
4;.75 Leica S4; Z=0.63x; A=0.75x aux Leica S4; Z=3.00x; A=0.75x aux  
4;1 Leica S4; Z=0.63x; A=1.00x (no aux) Leica S4; Z=3.00x; A=1.00x (no aux)  
4;1.6 Leica S4; Z=0.63x; A=1.60x aux Leica S4; Z=3.00x; A=1.60x aux  

6.2. The code

The code below may be cut-n-pasted into free42. 

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ (MRCONV)
@@@@ DSC: Convert Reticle Units to Physical Units
LBL "MRCONV"

LBL 01           @@@@ Conversion & Variable Menu Page
CLMENU
"A"
KEY 1 XEQ 11
"Z"
KEY 2 XEQ 12
"Rc"
KEY 3 XEQ 13
"CONV"
KEY 6 XEQ 14
KEY 7 GTO 03
KEY 8 GTO 02
KEY 9 GTO 00
MENU
STOP
GTO 01

LBL 02           @@@@ Quick Settings Menu Page #1
CLMENU
"8;.32"            @@@@ Setting: S8 with 0.32x aux
KEY 1 GTO 20       
"8;.63"            @@@@ Setting: S8 with 0.63x aux
KEY 2 GTO 21       
"8;1"              @@@@ Setting: S8 with no aux
KEY 3 GTO 22       
"8;1.6"            @@@@ Setting: S8 with 1.6x aux
KEY 4 GTO 23       
"8;2"              @@@@ Setting: S8 with 2x aux
KEY 5 GTO 24       
"ZZZ"              @@@@ Setting: Toggle Zoom
KEY 6 XEQ 25
KEY 7 GTO 01
KEY 8 GTO 03
KEY 9 GTO 00
MENU
STOP
GTO 02

LBL 03           @@@@ Quick Settings Menu Page #2
CLMENU
"4;.32"            @@@@ Setting: S4 with 0.32x aux
KEY 1 GTO 30       
"4;.5"             @@@@ Setting: S4 with 0.5x aux
KEY 2 GTO 31       
"4;.63"            @@@@ Setting: S4 with 0.63x aux
KEY 3 GTO 32       
"4;.75"            @@@@ Setting: S4 with 0.75x aux
KEY 4 GTO 33       
"4;1"              @@@@ Setting: S4 with no aux
KEY 5 GTO 34       
"4;1.6"            @@@@ Setting: S4 with 1.6x aux
KEY 6 XEQ 35
KEY 7 GTO 02
KEY 8 GTO 01
KEY 9 GTO 00
MENU
STOP
GTO 03

LBL 00           @@@@ Application Exit
EXITALL          
RTN              

LBL 11           @@@@ Code for menu key A
FC? 64           
STO "mrcvA"      
VIEW "mrcvA"     
RTN              
LBL 12           @@@@ Code for menu key Z
FC? 64           
STO "mrcvZ"      
VIEW "mrcvZ"     
RTN              
LBL 13           @@@@ Code for menu key Rc
FC? 64           
STO "mrcvRc"     
VIEW "mrcvRc"    
RTN              
LBL 14           @@@@ Code for menu key CONV
RCL× "mrcvRc"    
RCL÷ "mrcvA"     
RCL÷ "mrcvZ"     
RTN              

LBL 20           @@@@ Code for Setting S8: with 0.32x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.32               @@@@ A Value
STO "mrcvA"      
GTO 26             @@@@ Set Z Value
LBL 21           @@@@ Code for Setting: S8 with 0.63x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.63               @@@@ A Value
STO "mrcvA"      
GTO 26             @@@@ Set Z Value
LBL 22           @@@@ Code for Setting: S8 with no aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
1.00               @@@@ A Value
STO "mrcvA"      
GTO 26             @@@@ Set Z Value
LBL 23           @@@@ Code for Setting: S8 with 1.6x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
1.60               @@@@ A Value
STO "mrcvA"      
GTO 26             @@@@ Set Z Value
LBL 24           @@@@ Code for Setting: S8 with 2x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
2.00               @@@@ A Value
STO "mrcvA"      
GTO 26             @@@@ Set Z Value
LBL 25           @@@@ Code for Setting: EMPTY
GTO 26             @@@@ Set Z Value

LBL 26 @@@@ Drop X & set the zoom level for S8 Scope
R↓               
FC? 64           
1.0               @@@@ Z Value NO SHIFT
FS? 64           
8.0               @@@@ Z Value SHIFT
STO "mrcvZ"      
GTO 01

LBL 30           @@@@ Code for Setting: S4 with 0.32x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.32               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value
LBL 31           @@@@ Code for Setting: S4 with 0.5x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.50               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value
LBL 32           @@@@ Code for Setting: S4 with 0.63x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.63               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value
LBL 33           @@@@ Code for Setting: S4 with 0.75x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
0.75               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value
LBL 34           @@@@ Code for Setting: S4 with no aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
1.00               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value
LBL 35           @@@@ Code for Setting: S4 with 1.6x aux
1                  @@@@ Rc Value
STO "mrcvRc"     
R↓               
1.60               @@@@ A Value
STO "mrcvA"      
GTO 36             @@@@ Set Z Value

LBL 36 @@@@ Drop X & Set the zoom level for S4 Scope
R↓               
FC? 64           
0.63               @@@@ Z Value NO SHIFT
FS? 64           
3.0                @@@@ Z Value SHIFT
STO "mrcvZ"      
GTO 01

END

7. S-Series Leica Parts

Table 18: S-Series Leica Parts
  Leica Part # Leica Part Name
1 10446298 Leica S8 APO Microscope
1 10446293 Leica S4 E Microscope
2 10447136 10×/23B eyepiece for eyeglasses, fixed
4 10447137 10×/23B eyepiece for eyeglasses, adjustable, accepts reticles
  10447138 16×/15B eyepiece for eyeglasses, fixed
  10447139 16×/15B eyepiece for eyeglasses, adjustable, accepts reticles
  10447130 10×/23 eyepiece, fixed
  10447131 10×/23 eyepiece, adjustable, accepts reticles
  10447132 16×/16 eyepiece, fixed
  10447133 16×/16 eyepiece, adjustable, accepts reticles
  10447134 20×/12 eyepiece, fixed
  10447135 20×/12 eyepiece, adjustable, accepts reticles
  10446326 10x/23 eyepiece for eyeglasses, fixed
  10446329 10x/23 eyepiece for eyeglasses, adjustable, accepts reticles
  10445301 16x/14B eyepiece for eyeglasses, adjustable, accepts reticles, requires spacer
  10445302 25x/9.5B eyepiece for eyeglasses, adjustable, accepts reticles, requires spacer
  10445303 40x/6B eyepiece for eyeglasses, adjustable, accepts reticles, requires spacer
2 10446447 Reticle 10 mm/0.1 mm
  10446448 Reticle 5 mm/0.1 mm
  10446449 Reticle 5 mm/0.05 mm
  10447000 Reticle 100 scale intervals / 0.002"
  10447001 Reticle 100 scale intervals / 0.001"
  10447002 Reticle 150 scale intervals / 0.0005"
1 10446334 Achro Auxiliary \(0.32\times\) for S8APO, WD 200 mm
1 10446335 APO Auxiliary \(0.63\times\) for S8APO, WD 100 mm
  10446336 APO Auxiliary \(1.6\times\) for S8APO, WD 37 mm
1 10446337 APO Auxiliary \(2.0\times\) for S8APO, WD 25 mm
  10446316 Auxiliary \(0.32\times\) for S4/S6, WD 300 mm
1 10446318 Auxiliary \(0.5\times\) for S4/S6, WD 200 mm
1 10446319 Auxiliary \(0.63\times\) for S4/S6, WD 155 mm
1 10446320 Auxiliary \(0.75\times\) for S4/S6, WD 130 mm
1 10446321 Auxiliary \(1.6\times\) for S4/S6, WD 55 mm
1 10446322 Auxiliary \(2.0\times\) for S4/S6, WD 35 mm
  10446325 Auxiliary \(0.3–0.4\times\) for S4/S6 (Adjustable), WD 200–350mm
  10446323 Auxiliary \(0.6–0.75\times\) for S4/S6 (ErgoObjective) WD 77–137mm
  10446324 Lens shield
  10450831 Updated lens shield
1 10445928 Leica Video Objective \(0.32\times\)
1 10450528 Leica Video Objective \(0.5\times\)
  10447367 Leica Video Objective \(0.63\times\)
1 10446307 Leica Video Objective \(0.8\times\)

8. Image Sensor Data

Table 19: Image Sensor Data
Type Sensor \(S_w\) \(S_h\) \(I_w\) \(I_h\) \(S_d\) \(S_A\) \(I_{MP}\) \(P_w\) \(P_h\) \(P_{AR}\) \(P_{IJSPAR}\) Ref
1/4" IMX219 3.6800 2.760 3280 2464 4.60 10 8.1 1.122 1.120 1.00163 0.99838 IMX219
1/3.2" IMX179 3.2880 2.512 3280 2464 4.14 8 8.1 1.002 1.019 0.98328 1.01700 IMX179
1/2.5" MT9P031 5.7000 4.280 2592 1944 7.13 24 5.0 2.199 2.202 0.99883 1.00117 MT9P031
1/2.3" Leica mc170 6.1000 4.600 2592 1944 7.64 28 5.0 2.353 2.366 0.99457 1.00546 mc170
1/2.3" Leica mc190 6.1000 4.600 3648 2736 7.64 28 10.0 1.672 1.681 0.99457 1.00546 mc190
1/2.3" IMX477 RPI 6.2868 4.712 4056 3040 7.86 29 12.3 1.550 1.550 1.00000 1.00000 RPI
1/1.8" IMX334 7.9000 4.640 3952 2320 9.16 36 9.2 1.999 2.000 0.99949 1.00051 IMX334
2/3" IMX264 8.5000 7.100 2464 2056 11.08 60 5.1 3.450 3.453 0.99895 1.00105 IMX264
16mm film 10.3000 7.400 4120 2960 12.68 76 12.2 2.500 2.500 1.00000 1.00000 16mm
1" IMX183 13.1300 8.760 5472 3648 15.78 115 20.0 2.399 2.401 0.99924 1.00076 IMX183
1.1" IMX304 14.2000 10.400 4104 3006 17.60 147 12.3 3.460 3.460 1.00008 0.99992 IMX304
4/3" OMD EM1 M2 17.4000 13.000 5184 3888 21.72 226 20.2 3.356 3.344 1.00385 0.99617 OLY
APS-C Nikon D3200 23.2000 15.400 6016 4000 27.85 357 24.1 3.856 3.850 1.00166 0.99834 APSC
35mm film 36.0000 24.000 14400 9600 43.27 864 138.2 2.500 2.500 1.00000 1.00000 35mm

9. DIY RPI Camera

20251211_134106_200.jpg

Figure 1: A 30fps live feed illuminated only by my desk lamps. This is an exceptionally bright microscope.

9.1. The Idea

If you have arrived here via direct link, then you might be interested to know that your browser is pointed to the middle of a larger document – my personal stereo microscope notes. While these are my personal notes, I have attempted to expand this section a bit to make it easier to follow for someone wishing to replicate my camera setup.

Microscope cameras with built in image analysis software are pretty cool. Simply connect the camera to your monitor & mouse, and you can do simple image processing and measurement without a computer. These solutions are expensive for what you get, and the analysis software is pretty limited. So I thought, why not build my own? It's just a tiny computer and a camera in a compact case after all. If I used a Raspberry Pi, then I could actually run my favorite image analysis software (Fiji/ImageJ) right on the camera.

9.2. Bill Of Materials

Note: I originally built this camera around 2021, so the hardware listed below is pretty old (Pi model 4). The good news is that the software components described later work on newer Raspberry PIs, so you should be able to make a version of this project with modern hardware without too much difficulty.

Table 20: Bill Of Materials
Item Price (US $)
Raspberry Pi 4 Model B - 8 GB RAM 75
Raspberry Pi 4 Pro Mounting Plate for HQ Camera 7
Heatsink Raspberry Pi 4 Case with Dual Fans (NOTE) 26
Raspberry Pi High Quality HQ Camera - 12MP 50
MicroSD Card 15
Micro HDMI to HDMI Cable 12
CanaKit RPI 4 Power Supply with PiSwitch 11
Total 196

9.3. Wire Management

I like to be able to move the microscope around on my desk, so I have the whole thing on Teflon glider feet. This makes wire management a bit tricky. The power cable I purchased is quite sturdy and has a large EMI filter choke that's about the 10mm in diameter. I decided to use this as my primary cable mount point by clamping the choke into a small camera rig pipe mount which I connected to the 1/4" photographic mounting hole on the camera ring. I then routed all the wires parallel to the power cable, and encased them in a wire tube. I also added a couple zip-ties to secure the wire tube to the camera plate. The whole thing is pretty resilient.

20251211_135029_200.jpg

20251211_135035_200.jpg

20251211_135050_200.jpg

9.4. Wired Ethernet vs. WiFi

It's more than reasonable to use WiFi for this setup; however, things like software updates are a little slow. In the end I decided to use this super thin Ethernet cable I had in the cable box. Honestly if I hadn't had that cable laying around I probably would have stuck with WiFi.

9.5. Cooling Fan & Heat Sink Case

The fan is pretty unnecessary in my experience, and I generally keep it disconnected. The Pi can display a streaming view from the camera for hours without the temperature ever going over 50C in my lab (I keep the lab at about 20C).

If I were going to build this again, I would probably use the version of the case without the fan and save a couple dollars.

9.6. System Setup

First the Raspberry Pi must be configured – the OS installed & configured. The best place to start with that is probably the official "getting started" documentation.

The instructions below describe the next step of installing and configuring the camera related software. Note the following instructions are for the Debian Trixie (version 13) based Raspberry Pi OS released in October of 2025.

9.6.1. Minimal Configuration

The following steps should work for most people out of the box. The only tricky bit is Fiji because it is such a dynamic project, and things change over time. 

#### Install camera packages
sudo apt install -y libcamera-apps libcamera-dev rpicam-apps
#### Make sure we are in our home direcotory!
cd ~
#### Download Fiji software
test -e fiji-latest-linux-arm64-jdk.zip || wget 'https://downloads.imagej.net/fiji/latest/fiji-latest-linux-arm64-jdk.zip'
#### Unpack Fiji
unzip fiji-latest-linux-arm64-jdk.zip
#### If necessary, sync GIT repos from github.
if [ ! -e ~/world/my_prog/imagej/PhilaJ-and-RPI_Tools/ ] ; then
  git clone 'https://github.com/richmit/microscope.git'
  git clone 'https://github.com/richmit/imagej.git'
fi
#### Link the RPI_tools & optionally PhilaJ.ijm into Fiji
rm -f ~/Fiji/macros/toolsets/RPI_tools.ijm ~/Fiji/macros/toolsets/PhilaJ.ijm
if [ -e ~/world/my_prog/imagej/PhilaJ-and-RPI_Tools/ ] ; then
  ln -s ~/world/my_prog/imagej/PhilaJ-and-RPI_Tools/RPI_tools.ijm ~/Fiji/macros/toolsets/RPI_tools.ijm
  ln -s ~/world/my_prog/imagej/PhilaJ-and-RPI_Tools/PhilaJ.ijm    ~/Fiji/macros/toolsets/PhilaJ.ijm
else
   ln -s ~/imagej/PhilaJ-and-RPI_Tools/RPI_tools.ijm ~/Fiji.app/macros/toolsets/RPI_tools.ijm
   #### If you are a postage stamp collector, then you may want to also install PhilaJ
   #ln -s ~/imagej/PhilaJ-and-RPI_Tools/PhilaJ.ijm    ~/Fiji/macros/toolsets/PhilaJ.ijm
fi
#### Run Fiji and update
~/Fiji/fiji

9.6.2. My Configuration

Most Unix/Linux users have pretty strong opinions on how to setup a personal working environment. This section documents my personal configuration. I preform these steps before I do the stuff in the section Minimal Configuration.

  • I have a bunch of stuff in my home directory I sync (via rsync) from my primary workstation.
  • I like to have ruby, perl, & sbck in /usr/local/bin/ so scripts will work that refrnece those locations.
  • My dot files and ~/bin are automatically configured via SelectSetup.rb & SetupBin.rb.
  • My preferred user name is 'richmit'.
  • My preferred shell is 'zsh'.
  • Quite a bit more apt installed software (Emacs, sbcl, maxima, gnuplot, paraview, etc…)
9.6.2.1. System Setup
#### DO: Setup ssh (put pi-cam public key in .ssh directory)
#### Install my favorite  packages
sudo apt install -y emacs gnuplot maxima sbcl telnet zsh tmux gitk xterm imagemagick nomacs gimp ruby exiv2 git openssl
#### Make /usr/local links
for f in ruby perl sbcl; do
  if [ -e /usr/bin/$f ]; then
    sudo ln -s /usr/bin/$f /usr/local/bin/$f
  else
    echo Missing: /usr/bin/$f
  fi
done
#### Change my shell
sudo usermod -s /usr/bin/zsh richmit
#### Change root's password
sudo passwd root
#### Setup directories & links in $HOME
cd ~
for d in ~/bin ~/tmp/tmux/sockets ~/Pictures/pi-cam ~/synced/core/ ~/synced/Doc2/gadgets/leica_microscopes/; do
  mkdir -p $d
done
for d in pi-data/ dotfiles/ dotfilesSecure/ stuff/homeNetwork/ stuff/notes/ my_prog/learn/ex-ruby/              \
         my_prog/microscope/ my_prog/debianPackageTools/ my_prog/tmuxStuff/ my_prog/UNIXutils/ my_prog/utils/ \
         my_prog/ImageJ my_prog/mpms my_prog/dir-inventory/ stuff/my_ref/ my_prog/lispStuff/lispy/;             do
  mkdir -p ~/synced/world/$d
done
#### Make links to synced dirs
ln -s ~/synced/world ~/world
ln -s ~/synced/core ~/core
#### DO: Sync data from laptop via rsync
#### Setup dotfiles & ~/bin
./world/my_prog/UNIXutils/SelectSetup.rb --loc=HOME; ./world/my_prog/UNIXutils/SetupBin.rb
#### DO: Reboot
9.6.2.2. System Sync

I frequently sync my primary workstation with the pi-cam. The sync is bidirectional pulling data from the RPI (captured images & data) to my workstation, and to the RPI (scripts & config). I sync over the network using rsync via ssh. The commands below are executed on my primary workstation. 

date; echo back-dat-sync;        rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2                  --rsh='ssh' pi-cam:synced/pi-data/                                       /c/Users/richmit/Documents/world/pi-cam/;
date; echo back-pic-sync;        rsync -rlt --log-format=%f                            --modify-window=2                  --rsh='ssh' pi-cam:Pictures/pi-cam/                                      /c/Users/richmit/Pictures/pi-cam/;
date; echo microscope-code;      rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/microscope/               pi-cam:synced/world/my_prog/microscope/;
date; echo imagej-code;          rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/imagej/                   pi-cam:synced/world/my_prog/imagej/;
date; echo dotfiles;             rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/dotfiles/                         pi-cam:synced/world/dotfiles/;
date; echo dotfilesSecure;       rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/dotfilesSecure/                   pi-cam:synced/world/dotfilesSecure/;
date; echo homeNetwork;          rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/stuff/homeNetwork/                pi-cam:synced/world/stuff/homeNetwork/;
date; echo my_ref;               rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/stuff/my_ref/                     pi-cam:synced/world/stuff/my_ref/;
date; echo notes;                rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/stuff/notes/                      pi-cam:synced/world/stuff/notes/;
date; echo mpms;                 rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/mpms/                     pi-cam:synced/world/my_prog/mpms/;
date; echo mpms;                 rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/verGo/                    pi-cam:synced/world/my_prog/verGo/;
date; echo dir-inventory;        rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/dir-inventory/            pi-cam:synced/world/my_prog/dir-inventory/;
date; echo ruby-examples;        rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/learn/ex-ruby/            pi-cam:synced/world/my_prog/learn/ex-ruby/;
date; echo lispy;                rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/lispStuff/lispy/          pi-cam:synced/world/my_prog/lispStuff/lispy/;
date; echo line-sets;            rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/lineSets/                 pi-cam:synced/world/my_prog/lineSets/;
date; echo debianPackageTools;   rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/debianPackageTools/       pi-cam:synced/world/my_prog/debianPackageTools/;
date; echo tmuxHelper;           rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/tmuxHelper/               pi-cam:synced/world/my_prog/tmuxHelper/;
date; echo UNIXutils;            rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/UNIXutils/                pi-cam:synced/world/my_prog/UNIXutils/;
date; echo utils;                rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/world/my_prog/utils/                    pi-cam:synced/world/my_prog/utils/;
date; echo core;                 rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/core/                                   pi-cam:synced/core/;
date; echo leicaS8APO-docs;      rsync -rlt --log-format=%f --delete --delete-excluded --modify-window=2 --exclude '.git' --rsh='ssh' /c/Users/richmit/MJR/reading/Doc2/gadgets/leica_microscopes/ pi-cam:synced/Doc2/leica_microscopes/;
date

9.7. RPI Software

My goals:

  • Capture images directly from ImageJ/Fiji so I can immediately preform an image analysis
    • Setting image scale needs to be easy because measuring lengths is my #1 application
    • Identical UI between Windows and RPI
    • The software should be fully integrated into PhilaJ (an extensive set of ImageJ/Fiji macros for philatelic image analysis)
    • The microscope functionality should be available without the bulk of the PhilaJ user interface for people not interested in philately.
    • Optionally show a preview before capture
    • See a live view from the camera & control the size of the preview
    • Capture sequences of related images, and name so they are grouped together
    • Put captured images in a known directory with a standard naming convention so that it is simple to orginize and sync data between camear and computers

The ImageJ/Fiji toolset, called "RPI_tools", is actually a direct copy my "PhilaJ" software with an alternative, stripped down user interface that only exposes the microscope functionality. That is to say, the only difference between "RPI_tools" and "PhilaJ" is the ImageJ/Fiji toolset code the exposes the functionality to the end user. Full documentation may be found here:

https://richmit.github.io/imagej/PhilaJ.html#rpi-tools

The setup instructions above install this package into Fiji. You can find the code on github:

https://github.com/richmit/imagej