I just tested my Zeiss Contax G 35mm Planar with Fotodiox adapter on my NEX-7. In short, there is minimal real world color shift, but the lens suffers from very soft corners at wide apertures just like the ZM 35 Biogon. The ZM 35 seems to have noticeable color shift on the examples I\'ve seen. For reference, my ZM 50 Planar is sharp everywhere wide open.
Here are the results, all shot from a tripod with delay.
First, the white tissue test:
Very little vignetting or color shift, apparent at f/2. The real-world shots look fine.
Next, the full frame test shot at f/8:
Here are 100% crops from the frame center at f/2, f/2.8, f/4, f/5.6, and f/8:
The frame center looks pretty good to me from f/2.8 or certainly f/4 for most purposes. However, the corners and edges are pretty soft up to f/4, or even f/5.6, depending on your needs. Here are 100% crops from the upper left edge at f/2, f/2.8, f/4, f/5.6, and f/8:
Overall, I\'m happy with the performance, since I tend to shoot this FL at f/5.6 or f/8. Unfortunately, I haven\'t shot this lens on any other camera, so I can\'t say how sharp it should be.
Given the ZM 35 NEX-7 vs 5n tests, I suspect this lens would perform much better on the 5n.
