New adapter to use Contax 645 lenses on Nikon or Canon!

[lowep]

If I were to use the 210mm Contax 645 f4 lens with this adapter on a full frame Canon DSLR like the 5Dc the focal length would be the same ie 210mm (about 135mm 35mm equivalent), right?

Does that mean with the Contax 645 210mm lens on the Canon I would get an image covering the same area and coming just as close to the subject as with a 135mm Canon lens or a 210mm Canon lens? 

[alan_b]

If I were to use the 210mm Contax 645 f4 lens with this adapter on a full frame Canon DSLR like the 5Dc the focal length would be the same ie 210mm (about 135mm 35mm equivalent), right?

Does that mean with the Contax 645 210mm lens on the Canon I would get an image covering the same area and coming just as close to the subject as with a 135mm Canon lens or a 210mm Canon lens? 

Same as a Canon 210mm lens.

You'll just be illuminating your mirror box more with the Contax lens 

[lowep]

Thanks a lot Alan for the useful reply that helps me understand what would happen if I were to use this adapter to mount a Contax 645 lens on a Canikony 35mm ff (full frame) body

My understanding so far is this means:
210mm MF 645 lens on 645 body = 210mm (about the same angle of view as 135mm on 35mm ff camera)
210mm MF 645 lens on 35mm ff body = 210mm (same angle of view as 210mm 35mm lens on 35mm ff camera)

right?

does this also mean:
210mm 645 lens + MF 1.4x converter on 645 body = 300mm on 645 body (same angle of view as 180mm on 35mm ff camera)?
210mm 645 lens + MF 1.4x converter on 35mm film body = 300mm on 35mm body (same angle of view as 300mm on 35mm ff camera)?

this brings me to (yet) another question:
When mounting a 645 lens plus a teleconverter on a 35mm ff body via an adapter what if any difference in terms of functionality or image quality would there be if the teleconverter was designed for the 35mm body (eg Canon 1.4x, 2x) or the 645 lens (eg Contax 1.4)??

[MistralAtom]

I experience quite marked vignetting with this adapter beginning to be noticeable when 'stopped down' to the halfway mark.   This is true with 45mm, 80mm and 140mm Contax 645 lenses.  I have been delighted with the results with the 350mm f4.0 on a D3x.  It puts the lens that had been languishing back into use. 

[stefanooppo]

I finally bought the adapter and I want to warn all of you that it is only crap.
The desire of all of us who own beautiful Contax 645 lenses to finally use them will remain once again a dream.
The first time I mounted my 80 mm on my nikon D3 I couldn't believe to my eyes! Finally I can use it!
But after few shots i realize which is the problem:  the diafragm have to be  located in the focal center of the lens. If we put the diafragm in another location the lent won't work properly.
In fact we use the diafragm to have more depth of field, but the adapter diafragm just block the images after the focal point. So a diafragm located between the lens and the camera is not only useless but it affects the image creating a black ring . It is like using a nikon Dx lens in a full frame camera, you just miss a part of the image.
So with this adapter you can use your Contax Zeiss 645 lenses but only at full aperture.
My adapter also had a problem on the release leverage, so to detach it from my zeiss lens I had to use a screwdrive and open it.
Fortunately the shop accepted the return and gave me back the money.

[MistralAtom]

Now after a little more experience with this adapter.  I must agree with Stephanooppo.  It is not much more than a novelty. I don't doubt the lenses are secure when mounted, but the handicaps are so pronounced that it is pretty pointless. The diaphragm is absolutely without utility. The only saving grace is that the focus confirmation on Nikon works. I'm sure others have heard that electronics and autofocus operation within an adapter ARE possible.  See Leica S adapter C.  But the list price for that adapter is US $2,000 minus one cup of Starbucks house blend. Not to mention the cost of a Leica S body.