21mm Biogon on contax I ?

[Darinwc]

Will the 21mm f4.5 contax Biogon for on a contax I? The rear element sits deep in the camera.
And will it retain rangefinder coupling? (Not that it needs it)
Thanks!

 

[Cascadilla]

I just tried my 21 on my Contax I body. It won't mount because the knurled mounting ring on the lens hangs up on the shutter speed/winding knob. The 35 mm Jupiter 12 also won't mount for the same reason. The original brass mount 35 mm Biogon will mount on the Contax I. Hope that helps.

 

[Corran]

Strange - the 21mm Biogon I have mounts just fine on a late-model Contax I. Of course RF works fine too.

 

[Cascadilla]

It is strange--mine is a I f, as best I can tell based on the Kuc history and classification. But it definitely would not mount on the camera.

 

[Corran]

Mine is an 'f' model too as far as I know.

I have a nice post-war 35mm f/2.8 Biogon and the lens barrels are identical. They both mount with very little clearance. Here's a pic of the 21mm on the camera:

 

[Cascadilla]

I checked further with my 21 and post war 35 Biogon and the knurling of the lens meshes with the knurling of the shutter speed/film advance dial on my Contax I . My 85 mm Jupiter 9 will mount, but my post war Jena 8.5 cm f/2 Sonnar will not. Mine is, unfortunately, a shelf queen due to a dead shutter, so I had never checked this before. The Contax I is well known for having a lot of variations over its production run, so I guess this is yet another idiosyncrasy.