Inexpensive Chinese Contax Mount to LTM- Maybe a little work required.

Sonnar Brian

Sonnar Brian

Product of the Fifties
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EDITED: The design of this adapter has been changed and it can no longer be adjusted for external mount lenses.

For internal Mount lenses- the adapter works correctly. I will be keeping my two "first-version" adapters. The newer ones- dedicated for an internal mount lens only. I have a total of Five of these adapters now. For under $60- cheap enough to dedicate to some of my favorite Zeiss lenses.

I bought one of these almost 3 years ago, still available and still under $70.

The Amedeo adapters are works of art, his M-Mount adapter for internal mount Contax RF lenses has an indexed cam to correct the slight difference between the Zeiss 52.4mm focal length and the Leica. This Chinese adapter does not have an indexed cam, therefore the Internal Mount is best used with Nikon S-Mount lenses. If you use a Contax mount 50mm lens, you will probably have to increase the Shim for wide-open/ close-up.

When I used the adapter with external mount lenses: found the external mount did not line up with the lens. The mechanism was about 60degrees out of phase. Then- saw the three set screws on the side of the mount. This allows the external flanges to be moved relative to the helical. I set the mount in a Zeiss 135/4 lens, aligned it all- fastened the screws back down.

The adapter does not have an indexed cam, the RF cam moves 1:1 with the internal mount. Nikon S-Mount 5cm internal mount lenses will focus properly with the internal mount. The focus throw is 270degrees, which is the Zeiss standard. The RF cam moves from infinity to 0.9m meter with a 270degree throw. The Nikon external mount lenses cover the same range with a "ABOUT" 260degree turn. That means that Zeiss Contax external mount lenses will focus properly with the adapter.

The design flaw of the adapter- the back is shiny bare metal. No paint, no light baffles. Used with my pre-war Zeiss Triotar, I got some nasty reflections. The Triotar is an anastigmat, not a telephoto design. Basically, a larger format lens on a 35mm camera. The image circle illuminated the shiny metal of the RF cam of the adapter. I painted the back of the adapter Black, solved the problem.

But for $70- the focus was perfect with a Nikkor-SC 5cm F1.4 on my M Monochrom, and my pre-war 13.5cm F4 Sonnar and 8.5cm F4 Triotar.
 
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Thank you Brian. I have three Amedeo adapters, but none that works with the Contax mount 50mm lenses. I may have adapters for external mount lenses but not for internal mount lenses. Is it the other way around?
 
For $70- hard to beat. Conservation of Inconvenience, some work was required for the internal mount Contax 50. The Nikkor- was perfect.
 
I bought one of these branded Fotofox. It worked fine on a Helios-103, and a pre-war Zeiss 2/50. It was difficult to change lenses with it though. Eventually, it just fell apart.
 
Check the set screws- mine is almost a part of the Triotar now. The Triotar amazed me, I found a nice one for $100. I guess it was just "slow" for someone wanting a 8.5cm F2 Sonnar. I also have a dedicated indexed-cam adapter for the 8.5cm F2 Sonnar, stays on it.
 
I have emailed Amedeo a few times over the past couple of years, and bought a couple more adapters from him. So he's still around, living in Miami now. The adapters are still made in Venezuela by his machinist, due to the problems there, availability is spotty but they are still being made.

The last one I got was the LTM to Nikkor, so nice to be able to use S-mount lenses on my Barnacks. 🙂

I've never tried any of the cheaper options, but at some point I need to get one that works with the 50/1.5 Opton Sonnar.
 
Get Amedeo's for the Sonnar- it is perfect. The indexed Cam for the Sonnar was something he discussed here years ago.
 
Thanks for starting this thread, Brian. I just ordered the Fotofox adapter with the intent of using it to mount a Nikkor 5cm f1.4 on a Leica IIIc and Canon IVSB2. As I mentioned on another thread, several years ago I acquired a Kipon C-mount to LTM adapter, which I’ve successfully used with a Zeiss Opton Sonnar 5cm f2.0 on a IIIc. The Kipon adapters, alas, have gotten pricey. Amedeo is still the gold standard if you’re mounting a Nikkor or Contax RF lens on a Leica M camera. I wish Amedeo was able to make C-mount to LTM adapters again.

I checked ebay yesterday and there was an Orion Nikkor S-mount to LTM adapter for sale… for a mere $1,999!!
 
I would not buy the original unless it was back to low Earth Orbit.

The tolerances required for a good adapter are tight, and this makes it expensive. The Chinese lenses and adapters require "some user adjustments", which cuts the time required to produce them, and loosens tolerances for optics and mechanics. This is true of the 50/1.1 7Art lenses and the 75/1.25 7Art that I have. Same with this Fotofox adapter- but well work the time spent to use the Triotar on the Leica for a mere $70.

This Fotofox adapter is better than the adapters using a Kiev mount.
 
I have not tried the Fotofox adapters, but have used the Kipon for a number of years, it works well, and is nicely made. I also have 2 of the old Orion adapters, one bought fairly cheap on eBay ($300) about 10 years ago, and another attached to a 1951 J-3 with good glass in July 2021 for $310. Both are marked for Contax RF.
 
I have also had good luck with the Yeenon brand adapters available on eBay. I have an adapter for the Voigtlander Prominent mount Nokton to Sony E-mount, and another pair for Nikon/Contax RF mount to Nikon Z, both inner (for 50mm) and outer lens mount for the rest. Beautifully made, action is smooth as silk. I like that these adapters incorporate close focus features that transforms any lenses mounted to them into macro lenses, too.
 
If the FOTOFOX adapter works poorly, I may order one by Yeenon. Thanks for the feedback on your adapters. Kipon adapters may cost more than an Amedeo adapter.
 
About six months or so ago I bought an Amadeo adapter direct from Amadeo in Miami. He had two of them but claiming export issues with Venezuela where his machinist is located. I had to return the adapter as the focus was very very stiff. After returning, Amadeo kindly sent me another one. It wasn't much better so it went back too. Disappointing. I might buy one of these Chinese "wonders".
 
I suspect with Amedeo in Miami and his machinery being run by someone else: not as good. Amedeo discussed his technique, which involved much manual intervention with the CNC machine. I know my internal mount Adapters were made by him, bought a few years ago, The focus with the Millenium Nikkor is perfect, the same with the Indexed Cam Contax with my Zeiss Opton 50/1.5.

For someone wanting a very high precision adapter, and is willing to spend serious money on it- "WAIT a FEW MONTHS".
 
The Kiev external mount lenses should work with no problem. The rotation of the focus is the same as the Zeiss Contax. I used the adapter with an early black/nickel 13.5cm F4 and the Triotar 8.5cm F4.

The Internal mount lenses- will be slightly off, just like the internal mount Zeiss Sonnars. The adapter uses a Helical Pitch so the Cam travels to match the Leica RF as the lens rotates. The down-side, it does not travel far enough for the internal mount lenses made to the Zeiss standard,
 
raid said:
Which lenses are internal mount and which are external mount? Is it an obvious thing?
Click to expand...

Yeah - one goes inside the mount, the other goes around the outside of the mount.

Jokey snark aside (sorry, I couldn't resist!), all the Contax-mount 50mm lenses (so 50mm Zeiss Sonnars & Tessars, the Jupiters 3 & 8/8M, and the Helios 103) are internal mount. All other focal lengths have their own focusing helical and attach to the outer bayonet of the lens mount, totally covering the in-body focusing helical in the process.

There is one exception to the rule, though - the Kiev 5 didn't have an internal mount, so there's two special external mount 50mm lenses for it, the Jupiter-8NB and the Helios 94. I've never seen either in person but I believe they should - theoretically - work with any other Kiev or Contax camera (or Contax-to-Leica adapter).

On a related note, I always assumed the Helios 94 was just an external mount Helios 103, but having checked SovietCams, the lens diagram is different. It looks more like the front half of a Jupiter 8/50mm Sonnar combined with the back element of a Helios 103. Very weird. I'm half tempted to track one down to see what it's actually like to shoot now.
 
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