I searched around, but found no threads on this marvelous lens. I've played with a bunch of "legendary" manual lenses, but this one is definitely my favourite one.
Below is a link to a comparison with the Super-Takumar 85/1,9 (which isn't a bad lens either).
Actually, both have the samem42 screw mount, except the second one has some elongated shape, so it can only be used with adapters, which do not push the lever for the aperture all the time. Had two copies- both looked just like the latter.
Nevertheless, it has no problems with the mirror on 5D and makes just maginificent photographs (wanted to see some, that's why I posted here).
Anyway, here is a shot with it: http://photo.zvezdov.com/tests/bio_tak/_MG_0286.jpg
The Biotar seems pretty good at the wider apertures, but does not improve as much on stopping down compared to the Takumar. For the 400 euro, you might be better buying a used 90mm Summicron. The Summicron at f2 is probably better than the sample Biotar shot at f2.
The above was also shot at f/2. Do you reckon the Summicron would outperform it in terms of sharpness/contrast and bokeh? Which version should I be looking for? Any issues with the EOS system, compated to m42?
Fat biotars are about the same optically, as far as glass, but skinnies from 1930's and 1950's have 18 diaphragm blades for the best bokeh of any lens ever made when shooting at low f-stops. Tomioka 55mm f1.2 is another top bokeh lens but it might be soft wide open while Biotar 75/1.5 is sharp wide open, another thing it's known for.
At the above link you can see a 1930's biotar with bubbles in its glass competing favorably with Carl Zeiss Planar 85/1.4 on sharpness at low-f and better on bokeh. My particular 1930's is sharper than my particular 1951, but that is probably just not a primo 1951.
You would probably find the Summicron 90 to compare to CZ 85/1.4.
