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

TenEleven said:
You are right. But the shim is between two optical groups. As indicated in my crude drawing below.
This does two things - it shortens the focal length (from ~52.4mm actual closer to 51.6mm actual - the Nikon/Leica standard) and also moves the rear lens slightly further out from the focal plane. It's a two for one. Hope that clears things up.

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OK, the shim we are talking about and the one you have drawn in purple in your lens schematic is the shim between the two lens groupings...the shim I was referring to was the shim in the chrome lens mount...where the guy takes the whole lens Assembly out from its chrome lens mount , as seen at point 4:10 to 4:20 in the video. https://www.youtube.com/watch?v=CrExVkN7NVM&t=289s
 
Yeah you could increase the main-shim (which adjusts the register distance) by the appropriate amount and then put everything back together.

The method Brian suggested doesn't rely on modifying the shim, but achieves a similar end. It just means the shim will end up being in there a bit more loosely now after the lens got "screwed out" half a turn. Since most Helios-103 are screwed into the mount quite deeply and secured with two set screws (instead of just one as with Zeiss/Jupiters) it would be still mechanically secure.

Many ways to skin a cat and all that.

Edit: Usually I do Brians method, and then when I'm happy after a test shoot I re-do it "properly" making the right shim so that it fits snugly and then go about re-indexing the aperture as explained above.
 
TenEleven said:
Yeah you could increase the main-shim (which adjusts the register distance) by the appropriate amount and then put everything back together.

The method Brian suggested doesn't rely on modifying the shim, but achieves a similar end. It just means the shim will end up being in there a bit more loosely now after the lens got "screwed out" half a turn. Since most Helios-103 are screwed into the mount quite deeply and secured with two set screws (instead of just one as with Zeiss/Jupiters) it would be still mechanically secure.

Many ways to skin a cat and all that.
Click to expand...

So just increasing the thickness of the main shim, as shown in that video at point 4:10 to point 4:20 will do the trick...so 1980 to 1982 Helios 103 lenses had a shim between the two lens groupings, shown by the purple vertical line in your lens schematic drawing but in 1983 they removed this shim or they made it of little significance thickness ?
 
Either would do the trick.

Regarding the omission of the inter-element shim in later Helios lenses, that is something I do not know for sure. It's possible that they changed the manufacturing process so that the length of the optical mounting tube determines the correct focal length, but since this would require much more manual measuring, selecting and grouping of parts - aka more labor intensive - I doubt it. I guess I could take apart my 1984 one and have a look-see.

Edit: Did a quick disassembly. There are indeed no more inter-group shims and all the lens elements are just dropped in there loosely - Zeiss Opton style. The function of the shim is now done by a sort of mounting bucket that can be screwed in or out for the same effect. Mine is however frozen in place - I assume they epoxied it once they had it where they wanted.

Image from iOS.jpg
 
TenEleven said:
Either would do the trick.

Regarding the omission of the inter-element shim in later Helios lenses, that is something I do not know for sure. It's possible that they changed the manufacturing process so that the length of the optical mounting tube determines the correct focal length, but since this would require much more manual measuring, selecting and grouping of parts - aka more labor intensive - I doubt it. I guess I could take apart my 1984 one and have a look-see.
Click to expand...

It seemed continuous simplification of the Kiev 4M and 4AM camera models and their lenses was the goal...taken to extreme that many produced were not far from junk...the story I heard is a lot of made parts for those two last of the classic Kiev RF models were simply no good to be used in production and dumped into a land fill.
 
TenEleven said:
Either would do the trick.

Regarding the omission of the inter-element shim in later Helios lenses, that is something I do not know for sure. It's possible that they changed the manufacturing process so that the length of the optical mounting tube determines the correct focal length, but since this would require much more manual measuring, selecting and grouping of parts - aka more labor intensive - I doubt it. I guess I could take apart my 1984 one and have a look-see.

Edit: Did a quick disassembly. There are indeed no more inter-group shims and all the lens elements are just dropped in there loosely - Zeiss Opton style. The function of the shim is now done by a sort of mounting bucket that can be screwed in or out for the same effect. Mine is however frozen in place - I assume they epoxied it once they had it where they wanted.

Click to expand...

Thank you for taking the time to see if there is a inter-element shim on later made Helios 103 lenses...whether you have early made or later made post 1982 Helios 103 lenses..the simple Brian Sweeney procedure of making the lens suitable for use in Leica standard cameras would be the same, I am assuming?
 
The Simple Method usually works- assuming the lens works well on a Contax/Kiev to begin with. I found the Menopta and earlier 1981 and 1882 Helios-103's to have a better build quality, a Few of the later ones required some filing here and there to fit the Mount properly. I've probably gone through 20 of these lenses.
 
Sonnar Brian said:
The Simple Method usually works- assuming the lens works well on a Contax/Kiev to begin with. I found the Menopta and earlier 1981 and 1882 Helios-103's to have a better build quality, a Few of the later ones required some filing here and there to fit the Mount properly. I've probably gone through 20 of these lenses.
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You are right, Brian...the later made ones can be hard to fit them to the camera. I have a mid 1960s J-9 lens and it fits nicely on a 1962 Kiev 4 but on these early 1980s Kiev 4M and 4AM models it does not fit their lens mount and as you know it is the external bayonet mount.
 
Sonnar Brian said:
The Simple Method usually works- assuming the lens works well on a Contax/Kiev to begin with. I found the Menopta and earlier 1981 and 1882 Helios-103's to have a better build quality, a Few of the later ones required some filing here and there to fit the Mount properly. I've probably gone through 20 of these lenses.
Click to expand...

This corroborates my experience, my Helios-103 had to be filed (the little flag for the mount had to be filed down) as well as bending the bayonet springs back and forth a bit with a driver to make them more elastic. But since I got it for the nice price of free, that's fine with me.

A friends 1981 Helios-103 mounted easily right away and required no modification.
 
I bought a Fotofox adapter RF to L39. My experience is that it is a piece of s$%^. The L39 end would screw into the mount of a Bessa R but could not safely screw it into the mount of my IIIc or IIIf. Also, I could not mount a internal mount Tessar 2.8c, a CV Skopar 50 cs, or a Nikkor 35 s...The collars have a tab to secure the lens and the cutout for the tab was such that the tab would not engage and close. The focus binds as well. The jokers do not take returns. Now I know why. To be slightly fair, a year or so ago Amadeo sent me two separate adapters and they worked poorly. he refunded my $$ and apologized because that's all he had and could not smooth out the exports from Venezuela. Maybe now that's been reconciled.
 
update.......ebay notified me that the seller accepted my return request. so now waiting for a shipping label. We shall see.
 
I bought a second one. Like I stated originally, some work might be required. I got my 1932 Sonnar 5cm F1.5 in, one of the first 100 made. I now have Contax mount lenses from 1931 with a Tessar from the first batch of lenses made in Contax mount through to the Millenium Nikkor 50mm F1.4. There is no tight mechanical specification for the Contax/Nikkor/Kiev mount that is so tight that all manufacturers lenses fit in each others cameras and mounts. The 1932 Sonnar did not want to go into an Amedeo 50mm dedicated adapter. It did fit into an earlier Amedeo LTM adapter. I've learned not to force things. I've seen other lenses with broken locking tabs that were forced, Nikon and Zeiss. I've learned to file locking tabs of the Helios and Menopta lenses, and J-8 in Kiev mount. I'm not filing anything on the 1932 Sonnar, I will file the adapter and dedicate it to the lens if required. I have a couple of adapters dedicated to lenses as it is. For under $70, fitting the adapter to the lens is cheap.

I also have some J-3's and J-8's that screw just fine into a Leica but not into my Canon III. Again- learned not to force things and to look for the offending piece of metal that can be filed down.
 
The adapter I received mounted the early black/nickel CZJ 13.5cm F4 perfectly, and the 1930s Chrome 8.5cm F4 Triotar perfectly.

I used it with a 1955 KMZ Jupiter-9: the lock of the lens would not click into place. The mounting flange was a fraction of a millimeter off. I'm used to dealing with this. I decided to file the offending Brass of the adapter and dedicate it to this 1955 KMZ Jupiter-9. In the past, I've filed the locking tab of the Jupiter lenses to mount on a Contax and on a Nikon. I did a CLA on the J-9 (not as easy as a J-3), and shimmed it to be accurate from 1.15m to Infinity. You just cannot do that on the LTM version- I've tried, changed spacing of the elements and made a custom Adapter. I can get 1.3m to 20m at F2 with the LTM lens.

This one- is good enough to use across the full range.







The J-9 is under-corrected for spherical aberration. More like a Nikkor 10.5cm F2.5 than the Nikkor 8.5cm F2. I have an uncoated 1937 CZJ Sonnar with a custom adapter as well, but it does not focus as close as the J-9.
 




Final Adjustment to the Shim: Polished it down every-so-slightly with a 3M polishing sheet made for fiber optics. Last 0.02mm or so.






All wide-open on the M8.
 
Infinity focus on the distance scale completely agrees with the Rangefinder and the actual focus.



Mid Distance- accurate, RF, Distance scale, and actual focus.







Close Focus is accurate- RF, Distance Scale, and Image.



AND- this 1955 KMZ J-9 is the best I've ever seen.

L1024683.jpg


SO- for $70, this adapter is never coming off this lens.

You luck may vary. My second one arrived, focus is smooth. Your experience may be different- but probably no different from the other Four Adapters I own like this one, made for internal/external mount lenses and all required fiddling. Two are early Amedeo adapters and two are Russian, made from Kiev mounts. These cost much more than $70.
The difference with this adapter: The helical properly translates the rotation of a Contax lens to the Leica standard without using an indexed cam. Use it for External Mount Contax/Kiev lenses, and Internal Mount Nikon RF lenses. You can use it on a screwmount camera, and you can use it as an M-Mount adapter that brings up the correct framelines for your lens.

On the new adapter, again it was necessary to loosen the three set screws and orient the external mount flanges to the bayonet mount of the Contax lens. Be careful to tighten the screws evenly- driving one in farther than the others will put pressure on the helical and make focus uneven. I've had that happen on J-3's, so no surprise here.
 
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
 
etarbar said:
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
Click to expand...

Kelvin- you are correct in the observation that the Contax/Kiev mount lens rotates farther to reach the closest focus from infinity. That is the problem between the Contax and Nikon external mount. The 'C'ontax version of the 8.5cm F2 is going to work correctly with the adapter for Contax to Leica. The S-Mount version of the same lens will work with the Nikon S2 just fine. The focus of the Nikon S-Mount lens will be good enough on the Contax-Leica adapter at about F4. I am guestimating that number! The focus shifts towards infinity, and depth of field increases. When adapting a Nikon lens to focus better on a Contax camera, the shim (usually) need to be reduced slightly. The reverse is true for a Contax lens to be used on the Nikon- the shim usually needs to be increased.

I bought all three versions of the Nikkor-PC 8.5cm F2... S-Mount, Leica Mount, and Contax mount.

I would suggest buying the Nikon S-Mount 8.5cm F2 for primary use on the Nikon S2, and see how it works out on the Adapter.
Then: I would suggest buying a Contax/Kiev Jupiter-9 for use with the adapter on the LTM camera. The Bokeh of the J-9 is very smooth, and the J-9 on Contax/Kiev mount is not expensive.
 
Thank you very much, Brian.
The shim that need to be adjusted, is it the main shim?
Or is it another shim between the front and rear optical group?
After successful shimming, camera's rf patch will agree wilth the actual lens focus at any distance, correct?

I will follow your suggestion, get the s mount version lens first.
I have J9 LTM version and it's impossible to get the correct focus at every distance.
I hope this case should not happen in the contax version since there is no rf tube part.

Comparing Nik 8.5cm (brass) and J9 contax (aluminium),
i guess they have the same size, but Nik should be heavier.
 
Adjust the main shim on the Nikkor.

It is almost impossible to get a J-9 LTM to work wide-open at all distances.

Brian
 
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