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

Sonnar Brian said:
If the copper tape does not hang up on the mount, it does hold up. I've used copper tape to create a close-focus correction for using a CZJ 8.5cm F2 with a Contax to M-Mount adapter. 15 years ago.
Click to expand...
I was thinking about the idea of a tapered cam like on my Amedeo M adapter, but suspect that is over my ability to figure out at this point. I've got plenty of copper tape so will try to adjust for close focus at either f2 or f2.8 like I did for my Jupiter 8. I'm planning to use an f2 Sonnar on this adapter since that is a nice match with the smaller Barnack cameras, and I have the Amedeo for f1.5 lenses on M.
 
Sonnar Brian said:
For $53- the adapters are worth buying and pairing with a lens.

www.ebay.com

RF-L39 Adapter For Contax Rangefinder CRF RF Lens to Leica Mount SM M39 L39 | eBay

- With This Adapter, You Can used Contax Rangefinder CRF RF Lens on Leica Mount SM M39 L39 camera body. - Although the lens will fit physically, automatic diaphragm, auto-focusing, or any other functions will not operate correctly while using this adapter. - Infinity focus is guaranteed. -...
www.ebay.com

We'll see how it goes. I can always use it on Live view.
Click to expand...
I just got one of these in the mail, from that exact vendor. It works great with my Helios-103, which has been set to Nikon RF standard by unscrewing the mount 180deg. I was worried based on the posts recently in this thread, that it wouldn't couple properly with my M240. Reassuring to see that it couples with the rangefinder properly both at 0.7m and at infinity. To be clear, this is the CRF to LTM adapter listed in the ebay link above. Cheers!
 
Very cool and good to know.

jc031699 said:
I just got one of these in the mail, from that exact vendor. It works great with my Helios-103, which has been set to Nikon RF standard by unscrewing the mount 180deg. I was worried based on the posts recently in this thread, that it wouldn't couple properly with my M240. Reassuring to see that it couples with the rangefinder properly both at 0.7m and at infinity. To be clear, this is the CRF to LTM adapter listed in the ebay link above. Cheers!
Click to expand...
 
Last edited:
jc031699 said:
I just got one of these in the mail, from that exact vendor. It works great with my Helios-103, which has been set to Nikon RF standard by unscrewing the mount 180deg. I was worried based on the posts recently in this thread, that it wouldn't couple properly with my M240. Reassuring to see that it couples with the rangefinder properly both at 0.7m and at infinity. To be clear, this is the CRF to LTM adapter listed in the ebay link above. Cheers!
Click to expand...
I just bought another one for the restored 1933 Sonnar. The Cam is too long, and the adapter front-focuses using the RF of my M240. That can be fixed by polishing the cam down. This all means- luck of the draw. The manufacturing tolerances and quality control are very loose on these.
 
The RF Cam was driving the rangefinder past infinity. Actual infinity for the adapter was correct, and it could be used with Liveview.
8micron sand paper, followed by fiber-optic polishing sheets. Scary. I did not do any measurements, just polished until it looked good to me. I've been doing this for a long time. All using the RF of the M240.

RIMG0029.jpgRIMG0031.jpgM2405599.jpgM2405602.jpgM2405603.jpgM2405604.jpgM2405605.jpg

Wide-open, and F2.8 for the pairs.
 
One more, wide-open. I shimmed this early Sonnar to be between the Zeiss and Nikon (Leica) standard. I made the mount for it by cutting down a later mount. Aperture coupling is an I-26 screw, aperture ring made from scrap parts of too many lenses in a box to remember where they all came from.
M2405595.jpg

Some shots from yesterday, using Liveview. This is before I polished down the RF cam, which made using the RF unreliable. Sun was out. All wide-open. This lens is nice.
M2405584.jpgM2405585.jpgM2405587.jpg
 
Last edited:
Alright got an update. Just got in that cheap adapter that was posted up there, L39 screw mount. I paired it with a M39-LM adapter for 28-90 frame lines and the 50mm nikkor is now aligned both the LV and the RF patch. My other adapter for 35/135mm frame lines was out of phase a bit. It was less than the RF-LTM adapter, but still out of phase. I'm not sure if a 50/75 adapter will also be aligned as I don't have one, but I might order one since they're cheap already just to have it. Tried this on my M240P, not sure if this will transfer to a film camera.
 
If the LV and RF align with the one adapter for the 50mm lens, it means the other adapter has a slightly different thickness. Focus with the RF should still agree with liveview.
Does the adapter correctly focus to infinity?
 
I read through this whole thread, but sorry if I missed the answer to the question. Was there an issue with certain later model years of the Helios 103 by turning out the mount 180 degrees, or will that trick work with all of them? I have a Helios 103 coming (not sure what year) and debating whether to do the mod with my Amedeo external/internal Nikon adapter or to get one of the eBay ones that can presumably focus more closely (0.7m v. 0.9m).

And I assume that the eBay adapters will work out of the box with the 50mm f/1.4 Millennium Nikkor. Getting that closer focusing distance makes a big difference for me with RF 50s.
 
The early Helios-103 has a secondary shim for the rear group. You can take it out, and polish it down ~0.4mm to use on a Nikon RF camera, or the adapter.
The later Helios-103, easiest way to set for use on a Nikon is to undo the set screws and unscrew 1/2 turn, so that the hold for the set screws line-up again.
 
Sonnar Brian said:
If the LV and RF align with the one adapter for the 50mm lens, it means the other adapter has a slightly different thickness. Focus with the RF should still agree with liveview.
Does the adapter correctly focus to infinity?
Click to expand...
I'm going to come back with an update probably tomorrow or sometime this week. The pictures I took were just indoors, so didn't get really test for infinity.
 
So, is it safe to say that there is no currently-available alternative to the Amedeo, Coiro Optics (sold out anyway), or Kipon for RF-coupled external-mount Contax lenses?
 
That is accurate- no high quality, ready to use out of the box with a high probability of success.
These Chinese adapters are cheap, but either use them with Liveview or be prepared to hack them for use.
 
  • Like
Reactions: das
I mean without the link to listing itself we are reduced to guessing as to the contents of your image.
Most likely is an adapter made from a hacked-up Kiev. I have one of these (although mine is LTM and was made in Japan by some enterprising Japanese machinist) and it works alright. Not much sorcery involved, actually.
 
TenEleven said:
I mean without the link to listing itself we are reduced to guessing as to the contents of your image.
Most likely is an adapter made from a hacked-up Kiev. I have one of these (although mine is LTM and was made in Japan by some enterprising Japanese machinist) and it works alright. Not much sorcery involved, actually.
Click to expand...

Pardon Our Interruption...

www.ebay.com
 
das said:

Pardon Our Interruption...

www.ebay.com
Click to expand...
Thanks.

Yeah that is almost assuredly made from a hacked up Kiev judging by the distance scale engravings and the use marks on the inside and outside part of the bayonet.
They have cut a groove in the side, which I assume will be what they are using to limit focus travel since the stopper mechanism from the Kiev body is obviously gone.

It's relatively easy to do this conversion (for a machinist) since the helical of the Kiev/Contax/Nikon is fairly deep and thus can be easily cut to size and have a slope for the rangefinder cam cut into it. Always easier to cut material away than to add it back.

My DIY adapter is made similarly but uses a screw through the rangefinder cam (which then runs against the mount) to achieve the same thing.
 
I have two similar adapters made from Kiev mounts: they do work. The focus travel from 0.9m to infinity on the Contax/Kiev is slightly longer than for the Nikon S-Mount and Leica mount. This can be corrected by cutting an Index into the RF cam. I have one with such an index, but had to do a slight correction to use with a pre-war CZJ 8.5cm F2 Sonnar.
 
Quick question for those who have done the unscrewing mod to get the Helios 103 into Nikon RF spec. Does the 103 rear optical block normally come screwed all the way in? From unscrewing the rear optical block housing, the set screw indent slots on the inside were like a 1/2 turn out from flush or more. That means whoever assembled it originally did not put the set screws with the rear screwed all the way in. Is this normal?

Probably going to have to find someone with a digital M to check it out where the optical block screw position should be with a Nikon RF adapter. :/
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom