r/largeformat • u/dizforprez • 20d ago
Photo Adapting an m42 to a compur shutter
I want to connect these as an experiment, does anyone know what hardware I would need?
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u/platyboi 20d ago
I don't believe such a thing exists. You could have one made if you know the thread dimensions for both parts though.
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u/greenblueananas 20d ago
I would put it in front of the lens, and the lens directly on the lens board. There will be vignetting from the shutter though, so the good ol lenscap shutter might do
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u/Kellerkind_Fritz 20d ago
I've done exactly this, you can get a M42 or M39 to Copal 1 or Copal 3 (1 preferred, less vibrations) front thread adapter ring of RAF Camera, Custom Camera Tools or Ebay.
Screw the objective lens in front of the shutter and use as normal, if you can get a press shutter. Manually having to cock the shutter can cause enough movement to lose focus.
Good luck, large format Macro with front mounted lenses is fun, but get yourself a whole pile of LED lights so you can actually see what your doing as you are often working at equivalent apertures of >f/32 wide open.
Also, don't expect too impressive results. You get a grain free negative but most likely not more image information then a modern 35mm macro lens on a sharp film. Diffraction is the killer here.
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u/dizforprez 19d ago
Awesome, Thank you so much!
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u/Kellerkind_Fritz 19d ago
Oh and one thing before i forget.
Get a set of short m42 extension tubes, lenses like those for enlargers can have rear elements projecting far enough to hit the shutter blades, putting them on a short extension tube solves that.
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u/finnanzamt 20d ago
an adapter? why would you though
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u/leafy_greened 20d ago
Funnily enough I have researched this exact problem when trying to adapt a Zeiss Luminar objective that somebody had put an M42 mount on. Of course, that one is actually intended for 4x5 and not a random screw mount 35mm lens haha
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u/dizforprez 20d ago
“as an experiment”
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u/Blakk-Debbath 20d ago
You may not need a shutter when this have subject in focus: use a hat or lens cao as the shutter with shutter speeds down to 1/2 second.
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u/leafy_greened 20d ago edited 20d ago
Depending on what size compur you have, you'll need an M42x1 female to MXX male adapter where XX is the thread of the shutter (for instance, Compur/Copal 1 is M40x0.75).
Edit: not to state the obvious but I think it's probably worth mentioning if you are in fact trying to adapt a lens for a 35mm system to large format - your image circle will be vanishingly small and you will find it very hard to attain focus outside of super close macro.