N A values for various Stereoscopes

[Gatorengineer64]

Is therea list of NA values for various stereoscope? I have an SZH with the 1.0 Plan APO.... How does that stack up tosay a wild M8?

[PeteM]

My understanding (various sources - some of them OEM manuals) for 1X stereo objectives:

Original Olympus SZH Plan 1x: .087 na
Olympus DF Plan: .084 na
Nikon ED Plan: .090 na
Olympus DF Plapo: .100 na
Nikon Plan 1x: .105 na (I adapted one of these to an Olympus SZH10, where it performs well)

The early achromat 1x Wild objectives: .075 na

I don't know what the numerical aperture is for a 1x Wild Plan objective for the M8. Stephen might know.

Compared to either Olympus SZH/SZH10 or Nikon SMZ-U, the Wild M8 is wonderfully compact and elegantly built. That counts for something, especially if you want to lug a stereo scope around.

All these listings might be the ultimate achievable at full zoom magnification and subject to various fudge factors.

[Sliding Focus]

Is therea list of NA values for various stereoscope?

I am not aware of any such list, but it would be interesting to compile one! Here is a start...

Manufacturers often publish data on their stereomicroscopes' maximum NA (i.e. NA at maximum magnification) online, in promotional literature, and/or in manuals. Using these sources, here are the maximum NAs claimed for some stereomicroscopes (NB: a few values were inferred by halving those reported for a 'scope with a 2x objective installed):

Amscope
SM series (0.7–4.5x models): 0.065 @ 4.5x

Askania
SMC 4: ~0.11 @ 6.3x
SMT 4: ~0.1 @ 5x (with 1.6x binocular tube) or 6.3x (with 2x binocular tube)

Leica
EZ4: 0.057 @ 3.5x (version with 10x oculars) or 5.6x (version with 16x oculars)
S4 E: 0.062 @ 3x
S6/S6 E/S6 D/S6 T: 0.072 @ 4x
S7: 0.075 @ 4.5x
S8 APO/S APO: 0.1 @ 8x
S9/Ivesta 3 series: 0.0835 @ 5.5x
M50: 0.075 @ 4x
M60: 0.075 @ 4x
M80: 0.103 @ 6x
M125 C: 0.144 @ 10x
M165 C: 0.151 @ 12x
M205 C/M205 A: 0.175 @ 16x
MS5: 0.075 @ 4x
MZ6: 0.075 @ 4x
MZ7.5: 0.082 @ 5x with 1x planachromat, 0.103 @ 6.25x with 1x planapochromat
MZ9.5: 0.1 @ 6x with 1x planachromat, 0.125 @ 7.5x with 1x planapochromat
MZ12.5: 0.125 @ 10x
MZ16/MZ16 A: 0.14 @ 11.5x
Wild M10/MZAPO: 0.125 @ 8x

Nikon
SMZ18: 0.15 @ 13.5x
SMZ25: 0.156 @ 15.75x
SMZ800: 0.09 @ 6.3x with P-Plan 1x and P-ERG Plan 1x objectives, 0.1 @ 6.3x with P-Plan Apo 1x objective
SMZ800N: 0.105 @ 8x
SMZ1000: 0.09 @ 8x with P-Plan 1x and P-ERG Plan 1x objectives, 0.1 @ 8x with P-Plan Apo 1x objective
SMZ1270: 0.105 @ 8x
SMZ1500: 0.131 @ 11.25x

Olympus
SZ-III/SZ-Tr: 0.08 @ 4x
SZH: 0.084 @ 6.4x
SZH10: 0.087 @ 7x
SZX7: 0.10 @ 5.6x
SZX9: 0.10 @ 5.7x
SZX10: 0.1 @ 6.3x
SZX12: 0.110 @ 9x
SZX16: 0.15 @ 11.5x

Zeiss
SteREO Discovery.V8: 0.116 @ 8x
SteREO Discovery.V12: 0.144 @ 10x
SteREO Discovery.V20: 0.144 @ 15x

Sometimes, manufacturers report resolution data (in lp/mm or microns) instead of NA data for their stereomicroscopes; if one assumes that this resolution data can be converted to NA using the usual (approximate) formula of resolution (in lp/mm) = NA x 3000—which may or may not be a reasonable assumption—the following additional NA data can be inferred:

Bausch & Lomb
StereoZoom 4: ~0.05 @ 3x
StereoZoom 5: 0.067 @ 4x
StereoZoom 7: ~0.1 @ 7x

Zeiss
Stemi 305: 0.067 @ 4x
Stemi 508: 0.75 @ 5x
SV6: 0.0855 @ 5x
SV11: 0.0855 @ 6.6x

It would also be interesting to know ‘scopes’ NAs at various settings throughout their magnification range, as the NA value changes when the ‘scope is zoomed (or with different objectives or mag changer settings, for 'scopes with multiple fixed magnifications). Manufacturers rarely provide this data (though Leica reportedly will if asked), but people have occasionally attempted to measure it themselves. Gérard Weiss' estimates of the NAs for his AO 570 and David Walker's estimates of the NAs for his Meiji EMZ-1 and Leica S8 APO are particularly interesting. Also, NA values at all magnifications have been published for the following models with interchangeable objectives and/or stepped magnification settings:

Leitz Widefield Stereomicroscope
0.05 with 1x objective
0.065 with 1.6x objective
0.08 with 2.5x objective
0.08 with 4x objective
0.10 with 10x objective

Wild M5
0.0223 @ 0.6x
0.0445 @ 1.2x
0.0750 @ 2.5x
0.0800 @ 5x

Zeiss Stereo D and DRC
0.025 with 0.8x objective
0.03 with 1x objective
0.04 with 1.6x objective
0.04 with 2x objective
0.05 with 2.5x objective
0.07 with 4x objective
0.075 with 6.3x objective
0.05/0.08/0.12 with 2x/4x/8x turret-changer objective

Zeiss Stereomicrosope I/b
0.05 @ 2x
0.08 @ 4x
0.12 @ 8x

Further, for a handful of zoom stereomicroscopes, NA data for the lowest magnification setting (in addition to the highest) has been published: Amscope reports that the NA of their SM series 'scopes is 0.02 @ 0.7x, Nikon reports that their SMZ800N's NA is 0.0290 @ 1x and their SMZ1270's is 0.0285 @ 0.63x, and Olympus reported the NA of the SZ-III/SZ-Tr to be 0.04 @ 0.7x. Also, Bausch & Lomb's specs for the (measured) resolution of their StereoZoom 4 and StereoZoom 7 models at their respective lowest magnification settings of 0.7x and 1x would equate to NAs of 0.02 and 0.023.

I have an SZH with the 1.0 Plan APO.... How does that stack up tosay a wild M8?

Unfortunately, I have not found NA data for the Wild M8 with its OEM objective. However, PierreH has reported NA measurements for his Wild M8 fitted with a Leica 1x planapochromat objective, which increases the M8's magnification by 1.25x; assuming that that objective also increases the M8's NA by 1.25x (probably reasonable, as it does so when used on the M8's Leica-branded successors, the MZ7.5 and MZ9.5), then his measurements suggest that the maximum NA of an M8 with its OEM objective would be ~0.083–0.084, or about the same as the maximum NA of the Olympus SZH.

[apochronaut]

AO/Reichert 580 : ~ .09 @ 6X
Bestscope BS 3090/Optika SZR 180 and others : .15 @ 13.5X

[Gatorengineer64]

Tha KS full r the replies most helpful. I have an szh with the photo of adapter diopter and a chipped planapo that has the chip blackened. I was looking at either a better planapo or a different scope.

A cursory look doesnt seem to identify anything better that is many thousand more. The nikon objective sounds interesting. Any more info on what version or how it was adapted.?

Any other high na objectives that might be adaptable?