A correct Exakta to EOS adapter

alex ph · Joined: 16 Mar 2013 Posts: 1674

Dear fellows, those of you who use Exakta mount lenses (including Re.Topcor) on EOS body or on EOS adapters, could you please tell which ones work fine?

I've got a cheap Exakta to EOS adapter like this one which just does not grasp neither old Exakta lenses with the lateral shutter button (because the button prevents to put the adapter ring flat on the lens mount), nor the Re.Topcor lenses whish have an additional aperture pin (which does not fit any whole or channel and this prevents once again the ring to lay flat on the lens mount).

While there is nothing wrong with narrower Exakta to Nex cheap adapters like this one, I don't understand how the thin ones may sell without being constantly refused by the users.

I also see a more expensive version of Exakta-EOS like this one, but it does not seem to solve the main issue, as it is equallly large with only one main channel divided in two parts.

Please share your experience. Maybe I am just catching wrong the usage of the thing.

calvin83 · Joined: 12 Apr 2009 Posts: 7584 Location: Hong Kong

Your best bet maybe this one. However, no adapter will allow you mount all Re.Topcor lenses without modifying the lens.

Click here to see on Ebay

As the description is impossible to understand, here is the translation by myself.

cbass · Joined: 27 Jul 2019 Posts: 450

For Topcor lenses you do not have a good option that I know of.

You have this adapter which will work. However, I would expect an impact on image performance. That came with a used lens I purchased and it appears to be uncoated glass and impact iQ.

https://www.bhphotovideo.com/c/product/995133-REG/fotodiox_exa_eos_g_pro_canon_eos_ef.html

Your other option is this adapter. It had a slot cut inside it to deal with the aperture pin that sticks out on Topcor lenses:

https://www.ebay.com/itm/265496745469?chn=ps&mkevt=1&mkcid=28

That one they say is compatible with APS-C Canon cameras so you don't get FF. Also, in my case I was trying to use that to mount to a lens turbo and the pin from the lens stuck out too far and did not allow the lens to be mounted. At that point you are looking at shaving or removing the aperture pin, which would be a permeant probably irreversible modification.

calvin83 · Joined: 12 Apr 2009 Posts: 7584 Location: Hong Kong

cbass · Joined: 27 Jul 2019 Posts: 450

I think you may have had a different adapter. There is also a Exakta to EOS adapter made by Fotasy. It looks similar, but it has less slots cut out. The adapter I linked specifically says auto topcon to EOS and has additional slots for all the pins. However, it was still a failure for me. The adapter mounted to the lens without issue, but the aperture pin still stuck out beyond the thickness of the adapter and would not properly mount. Hence why I said there is no good option for Topcor. If you remove or shave off the aperture pin sticking out, then it should work but you alter the lens permanently. It's a hassle. Topcor lenses are easier adapted to mirrorless.

If you had the same adapter, then we ran into the same issue. That is why I first stated there is no good option. All options I know have issues. The first one with glass will work but IQ will be impacted.

calvin83 · Joined: 12 Apr 2009 Posts: 7584 Location: Hong Kong

Yes. We may got a different adapter but the result remains the same: the adapter will work only with the aperture pin filed down a little bit at least. The adapter I tried has a outer slot to accommodate the aperture ring too.

cbass · Joined: 27 Jul 2019 Posts: 450

That is correct. That adapter is still an issue. With Topcor your best chance is to have a mirrorless body.

Max78 · Joined: 14 Oct 2011 Posts: 80

John Shriver · Joined: 24 Dec 2009 Posts: 199

We need to convince the Leitax folks to make replacement mounts for Topcor lenses. Just one would handle every single RE. Auto-Topcor lens. Adapters to Canon EF and Pentax K would be very possible. They could also do Sony E, but why, since Canon and Pentax mounts can use adapters there. But to Nikon F is probably not possible, it would need to be too thin.

Unfortunately the R. Topcor lenses all have unique mounts, no two the same.

jamaeolus · Expire: 2015-08-20

I have an exakta adapter that has a very similar series of grooves. My guess is there are so many variations with exakta mount stuff its a bit hard to get a "one ring to rule them all" adapter.

alex ph · Joined: 16 Mar 2013 Posts: 1674

Thank you so much, fellows, for your tips and suggestions! I see now that there is a bunch of issues atatched to the common adapters.

Filing an additional cut in a basic adapter seems to be a partial solution.

Calvin, thank you for the translation of the hilarious annotation!

Max78, where did you get an M42 ring to replace the mount?

Max78 · Joined: 14 Oct 2011 Posts: 80

alex ph · Joined: 16 Mar 2013 Posts: 1674

Thanks for the precision. I searched ebay and found instead an add-on adapter, like this one, which looks pretty good for the purpose. What do you think of it?