Adapting non-OEM lenses to CMO stereo scopes
Posted: Thu Mar 02, 2023 7:18 pm
In what should have been evident to me a few years back (but wasn't), it's often possible to re-purpose other brands of stereo microscope objectives to the CMO scope of your choosing. Stephen was the one who alerted me to this. It's easy enough to roughly test compatibility by hand-holding the objective in place and making up a thread adapter.
This could allow many of us to get wide zoom range stereo scopes at more affordable prices.
In this case, I wanted to complete an affordable Olympus SZH scope without paying hundreds for used OEM objectives. The SZH has a thread diameter of M54 x 1mm. Pictured are an unknown (anyone recognize it?) 150 mm focal length objective, likely from a surgical scope, and a Nikon Plan 1x with an M58 x 1mm thread. This was initially meant for the Nikon SMZ 800/1000 series.
The cheap but likely achromat 150mm working distance objective has a roughly M67 x 1mm thread, adapted to M54. It gives about a .67 magnification and is parfocal from about 5x to 42.5x on the Olympus.
The Plan 1x Nikon objective has a stated numerical aperture of .105 at 80x, which apparently beats the stated 0.087 numerical aperture of the original SZH DF 1x Plan Apo and the .090 numerical aperture of the earlier Nikon 1x ED Plan. It could be that's an apples-to-oranges comparison. In any case, the Nikon, with a working distance of 78mm, loses 3mm in working distance to the Olympus Plan Apo (81mm WD) -- but it was cheap and available. It works beautifully and has the added advantage of taking widely-available 55mm filters, polarizers, wave plates, protective lenses, etc.
I've also adapted random objectives to Wild M3Z and M8, Leica MZ6, and Nikon SMZ-U scopes - with all able to be made parfocal and with no obviously introduced aberrations. That's not a guarantee, but most of these CMO scopes seem to have an infinity portion without much in the way of corrections in the tube lens or eyepieces.
Options for making up an adapter include turning one on a lathe, 3D printing, or buying a bespoke one. Camera and telescope thread adapters are often available in the needed sizes, making it possible to make up simple tubes and then epoxy the threaded adapter in place.
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This could allow many of us to get wide zoom range stereo scopes at more affordable prices.
In this case, I wanted to complete an affordable Olympus SZH scope without paying hundreds for used OEM objectives. The SZH has a thread diameter of M54 x 1mm. Pictured are an unknown (anyone recognize it?) 150 mm focal length objective, likely from a surgical scope, and a Nikon Plan 1x with an M58 x 1mm thread. This was initially meant for the Nikon SMZ 800/1000 series.
The cheap but likely achromat 150mm working distance objective has a roughly M67 x 1mm thread, adapted to M54. It gives about a .67 magnification and is parfocal from about 5x to 42.5x on the Olympus.
The Plan 1x Nikon objective has a stated numerical aperture of .105 at 80x, which apparently beats the stated 0.087 numerical aperture of the original SZH DF 1x Plan Apo and the .090 numerical aperture of the earlier Nikon 1x ED Plan. It could be that's an apples-to-oranges comparison. In any case, the Nikon, with a working distance of 78mm, loses 3mm in working distance to the Olympus Plan Apo (81mm WD) -- but it was cheap and available. It works beautifully and has the added advantage of taking widely-available 55mm filters, polarizers, wave plates, protective lenses, etc.
I've also adapted random objectives to Wild M3Z and M8, Leica MZ6, and Nikon SMZ-U scopes - with all able to be made parfocal and with no obviously introduced aberrations. That's not a guarantee, but most of these CMO scopes seem to have an infinity portion without much in the way of corrections in the tube lens or eyepieces.
Options for making up an adapter include turning one on a lathe, 3D printing, or buying a bespoke one. Camera and telescope thread adapters are often available in the needed sizes, making it possible to make up simple tubes and then epoxy the threaded adapter in place.
.
.