Contax I-III CRM mount?

[wolan]

Hi,
I reading on this page http://allphotolenses.com/lenses/item/c_4243.html that the Helios-103 and actually many other lenses, like the Carl Zeiss Jena Sonnar T 50mm f1.5 have a mont designed as "Contax I-III (CRM)"

A have a few questions:
- what does CRM mean?
- I understand that I and III mean the mount of the Contax I and III (range finder) cameras, correct?
- how does this relate to the Kiev Contax RF mount?

Thanks in advance.

[Sjak]

The Kiev RF camera's were copies of Contax camera's: https://en.wikipedia.org/wiki/Kiev_(brand)#Kiev_35_mm_cameras

[sergtum]

[newst]

CRM is definitely an acronym for Contax Rangefinder Mount.

There are minor differences between the Contax, Kiev, and Nikon S rangefinder mounts. Most of the difference is in the shape of the roller that guides the rangefinder/lens interface on the Zeiss Contax, Kiev and Nikon S camera mounts. The angle of the face of the roller in each camera design is different, not exactly matching the angle on the lens ring for different camera types. It might have caused some focusing problems when using a different manufacturers lens on your film camera, but it is of no significance when using any of those lenses on a modern, digital camera.

There is one other consideration, in the 1960s Zeiss Opton tried making their Contax Rangefinder cameras more competitive by making them smaller (Contax 2a and Contax 3a). When they did that they had to redesign their Biogon wide angle lenses because the rear element would interfere with the camera shutter. The redesigned lenses by Zeiss Opton are usable on Sony APS-C cameras where the earlier Biogons and Soviet Jupiter 12s aren't.