Contax rnagefinder lens on Sony 7R camera body

biogon44

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I have been successful in mounting my Zeiss Contax rangefinder Biogon21mm f4.5 lens on my full-frame Sony 7R camera body without any clearance problem. I have used a Contax (outside mount) to Leica M adapter, then adding a Leica M to Sony 7R adapter with helicoid component. With this arrangement, I have made this lens capable of being focussed from 'infinity' to near range. However, at 'infinity' setting, it is slightly unsharp. As my two adapters have been made to the highest standard, I believe that the lens elements are not properly positioned within this lens. I feel that re-collimation of the lens is necessary to ensure image sharpness at 'infinity'. Any comments about my difficulty and optical solution would be much appreciated
 

edmsnap

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This, of course, is a µ4/3 forum, so our suggestion might be to buy a µ4/3 camera where contax can be mounted with relative ease :biggrin:
 

G1 User

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Are you sure it not a Adapter problem? That is better fixed by adjusting the lens to "That" adapter combo.
What, I mean is, do you have a local camera repair that can adjust the lens INF stop to work with your Sony + 2 adapters.

I have a 1953 J9 in Contax/Kiev RF mount, (Zeiss 85mm f/2 clone), that I had to have one of the three spacers taken out, and the INF stop adjusted to use on my Fuji X-E2 with a simple Nikon S to Fuji adapter.

even with good adapters, there may still be some thickness problems after it is all said and done...
That might be enough to throw off the INF,
 

Serhan

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You can post your Sony A7R questions at our sister forum: http://www.talkemount.com/

Most of the rf lenses wider then 35mm esp the biogons have corner sharpness/color problems on 7R due to increased MP. A7 is a little better, but still struggles with biogons. I read that low MP A7S is the best for the wide rf lenses like the Voigtlander 15mm, but I have not seen reports on biogons. You can also check Fred Miranda-FM alternative forums which has more A7/A7R users with experiences with similar alt. lenses.
 

biogon44

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This, of course, is a µ4/3 forum, so our suggestion might be to buy a µ4/3 camera where contax can be mounted with relative ease :biggrin:
I would hope that this Forum is not as restrictive as you state in your reply. I would also feel that any information about using a vintage lens on any digital mirrorless camera body, regardless of specification, would be considered valuable for the members of this group. For your information, I do own several Micro 4/3rds camera bodies made by Panasonic. I know, from personal trial, that this particular Contax lens cannot be fitted onto my Panasonic Micro 4/3rds bodies, nor any other Micro 4/3rds brand. This Carl Zeiss Biogon21mm f4.5 Contax Rangefinder lens does, however, fit nicely into the full-frame Sony 7R mirrorless camera body. Please refrain from offering a suggestion where your specific knowledge is lacking and your general comment then becomes totally worthless.
 

pellicle

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I would hope that this Forum is not as restrictive as you state in your reply. I would also feel that any information about using a vintage lens on any digital mirrorless camera body, regardless of specification, would be considered valuable for the members of this group
oh? Well then I've got these Funinon 90mm and 180mm lenses for 4x5, do you know an adapter for that

I've also been wondering about converting my 4x5 camera back to accept the Graflex style backs so that when I use my 120 roll film holder in there its not needing me to really strech back the springs on the universal back.

I use my micro4/3 as my metering system for this ...

I know this may be shocking, but my view is that the A7 has a much bigger sensor and mount issues on it will bear zero usefulness to micro43. For a start the bigger sensor means that any issues of parallel surfaces are magnified ... but of course you can help me with my Large Format question , because naturally you're not so restrictive as to just limit this to digital? I mean its about mirrorless cameras ... remembering my 4x5 camera does not have a reflex mirror either ... right?
 

pellicle

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Are you sure it not a Adapter problem? That is better fixed by adjusting the lens to "That" adapter combo.
I would tend to agree with this. I've found that some 120 grit emery paper on a flat sheet (say glass) and a few gentle evenly pressured circles (wax on / wax off style) can bring the adapter mount down the few hundredths of a mm to make the difference with short focal length lenses (like 21mm).
 

broody

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From what I've read biogons may not play well with digital sensors because of the high telecentricity requirements. But I'm sure someone with actual experience with the lens will be more helpful!
 
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