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

Hello Brian, I'm Kelvin from Thailand.
Thank you so much for this post, very useful with all detail that I was looking for.
I bought 'Laina'; also Chinese made Contax rf to ltm adapter in chrome, to use with my Leotax model f, Canon IVSb, and Leica M2.
Using with Nikkor-S•C 5cm f/1.4 and 5cm f/2, I got accurate focus from infinity to close focus, also agree with camera's rangefinder patch. It's great!

Using with external mount need 60 degree turn to correct the position. And some filing the part that catch with lens' locking tab.
For Jupiter-12 35mm f/2.8, both adapter and collar ring of the lens need some filing to allow the fully catching inside the adapter and avoid interferring with camera's rf arm.
For Nikkor-W•C 3.5cm f/2.5, nothing to do with the lens, but the adapter need the work that I done for J12.
I also got everything accurate for both lenses.
I noticed that J12 need more rotation degree to reach pass 0.9m than Nik that stop at 3ft.

Nikon S2 is my new member and now I'm looking for Nikkor-P•C 8.5cm f/2.
May I ask for your suggestion which version should I get, Contax or Nikon?
I prefer to use the lens on both Nikon S2 and LTM/M camera with the adapter. I will use it mostly for portrait, close distance, full aperture.

If I go with 'C' version, it will fully compatible (correct rf&focus) with the adapter but need rear group shimming to make it work correcrly with S2, is this correct?

How about 8.5cm Nikon version? What should be done to make it work correctly with the adapter?

Thank you so much for kind advices in advance.
Kelvin
Kelvin, I was wondering if you could elaborate on this:
“Using with external mount need 60 degree turn to correct the position.”

Are you saying that you had to turn the helical 60deg to get the external mount to line up with the focus mount?

Or did you need to rotate the external mount by loosening the 3 set screws?

I have the Laina adapter and the rangefinder is off when using a Jupiter 9. Even after removing the 3 set screws, I could not get the external mount to move. (Not sure what the set screws do, then!) Maybe it is glued also…
 
Kelvin, I was wondering if you could elaborate on this:
“Using with external mount need 60 degree turn to correct the position.”

Are you saying that you had to turn the helical 60deg to get the external mount to line up with the focus mount?

Or did you need to rotate the external mount by loosening the 3 set screws?

I have the Laina adapter and the rangefinder is off when using a Jupiter 9. Even after removing the 3 set screws, I could not get the external mount to move. (Not sure what the set screws do, then!) Maybe it is glued also…
I bought three of these adapters over ~3 years. The first two allowed me to undo the 3 set screws and position the bayonet flange to agree with the Jupiter-9, which happens to be the best I have ever seen and am lucky to own it. The Third One: the design has changed somehow. Still has 3 set screws, but the mount cannot be repositioned. I use it exclusively with a post-war Carl Zeiss 50/1.5 internal mount lens. That lens: when bought, did not have a Contax mount and was unusable. I had a spare mount, and shimmed it for the adapter.
 
Just like Brian explained, the Laina adapter (chromed brass, excellent construction otherwise) does not work with external mount lenses for rangefinder coupling. The helicoid rotates ~85deg further toward infinity then it is supposed to. The two red dots should NOT be able to align, when comparing with Contax mounts. This is misassembled and not fixable. For internal bayonet lenses, the misalignment is irrelevant. The one problem is that the actual focal length for Leica is different than Contax RF, so this will only work if the Contax 50mm lens is rotated out of its mount ~180deg. It should work for Nikon RF internal mount lenses though.

I was able to unscrew my pre-war uncoated Zeiss Sonnar 50/1.5 180 degrees precisely and get perfect focus at all distances, when mounted in this adapter though, which means the tolerances are otherwise excellent. This lens is SHARP. The helicoid is very smooth and precise feeling. A shame, someone said "how do we press this ring into the base?" and the supervisor said "line up the red dots!". Not so.

See markings on photos for details.crf correct.jpgcrf incorrect.jpg
 
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A quick thought and question- it seems likely that the ~85 degree over rotation of the helicoid toward infinity could be fixed by finding a different entry point. However, I haven’t found a way to fully unscrew the helicoid on my Laina adapter. Anyone ever been able to do this?
 
I looked at my Fotofox adapter- no obvious way, I still cannot figure out why undoing the 3 set screws has no effect, unless the part was somehow glued.
 
I looked at my Fotofox adapter- no obvious way, I still cannot figure out why undoing the 3 set screws has no effect, unless the part was somehow glued.
It looks like they copied the Kipon design, but at some point changed to a press fit or glued juncture instead of relying on the screws. The precision of that interface between the external bayonet and the focus unit is impressively tight / precise and perfect on the Laina. Almost like it was machined after assembly.
 
This is a pity. I may still get a Fotofox to use with 50's because it's cheap but it would have been so nice to have the older version, alas.
 
Hi my name is canis I am new to the forum.
Is there any diffrence betweeen the LAINA and the fotofox adaptor? Both are made from brass and to my eyes
they look identical except for the lettering. Even the assembly is made the same false way compared with a regular
Kiev /Contax cameramount.

canis
 
Hi my name is canis I am new to the forum.
Is there any diffrence betweeen the LAINA and the fotofox adaptor? Both are made from brass and to my eyes
they look identical except for the lettering. Even the assembly is made the same false way compared with a regular
Kiev /Contax cameramount.

canis
Laina is chromed brass. Fotofox is anodized aluminum.
 
Hi jc...
there are 2 versions sold by Fotofox a black anodized and a chromed brass version. the chromed looks eactly like the LAINA except the lettering

canis
 
here are the auction from LAINA and FOTOFOX

black anodized
 
Recently, I've reconsidered these adapters and using my Kiev/Contax lenses on Leica bodies.
Brian had me rather encouraged when he started this thread. But now, I'm leary and confused. I look at the Fotofox (and clone) adapters on ebay and the ad copy always states "- Adapter has manual focus ring. but can not linkage focusing." To me, that means no rangefinder coupling. I'm not interested in doing an adaption if its not going to couple with the RF...
Are they correct? Or, perhaps the Chinese sellers are confused and not familiar with English and the adapter actually does couple?
 
The original Contax to LTM adapters provided correct RF coupling, and had set screws that allowed the external bayonet mount to be lined up with your lens. I have two of those, dedicated one to the best J-9 I've ever seen.

The newer version looks identical, but can no longer be adjusted to line up the external mount. I dedicated it to a Zeiss Opton 50/1.5 Sonnar. The very latest M-Mount version has an RF cam, but it is so far off it is useless for RF coupling. I could hack a metal ring on to it and correct that, but decided to dedicate it for Mirrorless use with my 5.8cm F1.5 Sonnar.

SO: was a good design, screwed it up half-way, then totally screwed it up. Same price.
 
The newer LTM version still works for internal mount 50mm Contax mount lenses if adjusted to Nikon RF focus calibration (have to shim or unscrew the internal bayonet mount 1/2 turn). The newer LTM mount version does not work with external mount (non-50mm) Contax lenses because the focus cam is mis-clocked. By “work” I mean focuses properly using the rangefinder.
 
Because of watching this thread over time, I ordered an Amedo Nikon to M adapter from Cameraguest today. I would have prefered the older inexpensive ones but knowing that one will _work_ is more important.
 
Ah. I should have pounced back when Brian first told us about these. I have a J8M and H103 in mind that I wanted to try.
Strange how the Chinese folks slowly made the adapters unusable...
No doubt the Amadeos are excellent but cost to curiosity ratio for my two 50's is too steep. I must have 10 or more other 50's in the cupboard without need for adapting.....
 
Ah. I should have pounced back when Brian first told us about these. I have a J8M and H103 in mind that I wanted to try.
Strange how the Chinese folks slowly made the adapters unusable...
No doubt the Amadeos are excellent but cost to curiosity ratio for my two 50's is too steep. I must have 10 or more other 50's in the cupboard without need for adapting.....
Understand.

I have enough lenses that I've gotten on the other side of that threshold for Nikon RF glass (and I intend to get more for both digital and film use) so it makes sense to invest in one now.
 
I recently got an RF to LM mount adapter from aliexpress to use my Nikkor S.C 50mm f1.4 lens with my M240P. I'm having a bit of an issue, not sure if others have had this, but the mount and lens work fine, however it seems my RF patch is out of phase with this lens or with the adapter. I need to use LV to focus correctly. Now I'm trying to see if I can either adjust the lens or the mount to get it the rf patch in phase. I tested other lenses and its not the camera RF that is out misaligned, so ruled that out. The lens is an internal mount lens btw. Any suggestions would be appreciated, thanks!
 
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