Orion type Contax / Nikon to M adapters

[james_cooke]

Im looking into getting one of these adapters and have found that the Nikon

versions are scarce but Contax ones are reasonable to find. If I am only using

internal mount 50mm lenses that dont have their own focusing helix, would it

matter if I just get a Contax adapter and use it with Nikon, Contax or Russian

50's? Or is there something more to the difference in Contax and Nikon

rangefinder lenses other than the difference in the helix that I havent

considered? Many thanks

[john_shriver]

You will still have focusing inaccuracies, since the focal length of the "50mm" lens will not match the helix in the adapter. Wide angle lenses are where it's a "doesn't really matter".

[james_cooke]

In what way do you mean it will not match the adapter? My understanding is that one turns around greater than the other to go from infinity to minimum focus and that the discrepancy occurs with the rangefinder coupling is adjusted accordingly. So if the lens doesn't have its own helix how would it matter how much longer or shorter it takes to get from infinity to minimum focus as long as it gets there by the adapter which is calibrated to match the M rangefinder in any event? I don't doubt that your right, im just curious why it would be so.

[fred_c1]

<a href=http://cameraquest.com/NRF-Contax.htm>Nikon RF - Contax RF Lens Compatibility</a><P>

<a href=http://www.dantestella.com/technical/compat.html>Ivan the Incompatible</a>

[just eric]

I purchased and subsequently returned one of those adapters sold on that auction site. The focus on a wide open 50 f1.5 Sonnar was off by about a foot close up and off in other ranges. I believe most of the adapters are made from donor Kievs. Maybe I had an isolated bad example, but be sure you can return it.

 

Eric

[paul t]

You can get the adapter shimmed. I bought one fomr Johnny Luk that was off by around 8

inches using my R-D1; I returned it, told him I wanted one tested with a 50/1.5 Sonnar,

and the new one seemed to work pretty well. So yes, make sure you get return rights.

<p>

It might be that you have to make some compromises with the 50/1.5 Sonnar in any case,

as this lens does exhibit focus shift at wider apertures. Look over at rangefinderforum

where there are some very informed posts. Brian Sweeney, I believe his name is, has set up

quite a few of these, and believes they work better with Nikon lenses than with Contax

ones, thanks to the slight difference in register.

[james_cooke]

Interesting comments and links thanks. Just to clarify, the 3 lenses I wanted to use with this adapter (all internal bayonet mount) are the Sonnar 50mm f2.0, Nikkor 50mm f1.4, and the Heliar S 50mm f3.5. With a Contax adapter will be fine with the Sonnar and hopefully the Heliar being a bit slow(?) and just wont be able to use the Nikkor wide open and close up I guess.

[furcafe]

As Eric Mah wrote, quality control on the new adapters can be variable. Indeed, they can be variable on the original adapters, too, though it can work to your advantage. For example, I have an original Cook & Perkins adapter &, for whatever reason (quality control, damage or botched repair, or intentional modification), it works better w/Nikon RF lenses than the intended Contax RF lenses.