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Archive 2016 · C-mount to t-mount to eos, no correcting optics?

  
 
Aaron D
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p.1 #1 · p.1 #1 · C-mount to t-mount to eos, no correcting optics?


Im asking here, as well as the Canon forum (for best results hopefully).

For a while, I've been interested in trying a wide fl, large aperture c-mount lens on my Canon bodies.

But from my knowledge, a no-optics adapter won't allow for infinity. (We dont want extra optics in our adapters!) However, I found a post somewhere stating "c-mount to t-mount to ef".

Can anybody confirm this? My google foo seems weak these days.

Thanks
Aaron



Feb 08, 2016 at 09:18 PM
jcolwell
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p.1 #2 · p.1 #2 · C-mount to t-mount to eos, no correcting optics?


You should rest your google. It'll come back.

The C-mount register (lens mount to sensor distance) is 17.5mm. The Canon EOS register is 44.0 mm. That means, in order to achieve infinity focus with a C-mount lens on an EOS camera (without adjusting optics in the adapter), you have to stick the butt of the C-mount lens 26.5mm inside of the front of the EOS camera.

IOW, no.



© jcolwell 2016




Feb 08, 2016 at 09:36 PM
freaklikeme
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p.1 #3 · p.1 #3 · C-mount to t-mount to eos, no correcting optics?


IIRC, the biggest frame C-mount used was super16, which is smaller than a m43's sensor. They make adapters for that mount that will work. You could pick up a cheap little Oly body and waste less of the frame. And you'd get IBIS.


Feb 08, 2016 at 11:54 PM
killersnowman
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p.1 #4 · p.1 #4 · C-mount to t-mount to eos, no correcting optics?


Nice spread sheet

jcolwell wrote:
You should rest your google. It'll come back.

The C-mount register (lens mount to sensor distance) is 17.5mm. The Canon EOS register is 44.0 mm. That means, in order to achieve infinity focus with a C-mount lens on an EOS camera (without adjusting optics in the adapter), you have to stick the butt of the C-mount lens 26.5mm inside of the front of the EOS camera.

IOW, no.




Feb 09, 2016 at 01:19 AM
paulhofseth
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p.1 #5 · p.1 #5 · C-mount to t-mount to eos, no correcting optics?


Some Cmounts, especially longer focal lengths, work with neglible vignetting on MFT. Others, mainly wide-angles, have a clear cutoff.

Adapters differ. For fast C-lenses, they need to acommodate optics that may be quite large, even at the mount-end. For the lens you wish to adapt, the outer diameter of the Cmount at the plane of the flange must be a bit less than the diameter of the MFT lens mount opening, while the lens itself can be thicker. Of the faster ones, the 50mm Schneider Xenon 0,95 performs well.

In the case of manually focussing some more specialized C-mounts, the electric contacts just inside the MFT mount have no function and may get in the way of the rear elements. No obvious solution in that case.

p.



Feb 09, 2016 at 02:42 AM
Aaron D
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p.1 #6 · p.1 #6 · C-mount to t-mount to eos, no correcting optics?


Thanks for the spreadsheet Jim! Very handy. I thought what I had seen in the past was adapted to an Ef mount. Turns out it was on an Eos-m/Ef-m. I have my eyes on cheap gh1s just to maybe try these.

I need to look into m4/3 IBIS bodies, as that would work great on my small collection of old MF lenses.

Aaron



Feb 11, 2016 at 01:08 AM





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