The first thing that gripped me was how beautiful the bokeh is from this lens. It almost has that cinematic feel to it. When focused close and wide open, it exhibits slightly swirling background which is not as apparent when used on the NEX-6 with a smaller sensor. I absolutely adore the bokeh and I think it's wonderful. One of the reasons I missed full frame was seeing the full image as the lens was designed to capture, rather than just a the middle of it with cropped sensors.
Wide open, the lens has very severe vignetting of at least 1.5 stops. The last picture shows the exposure difference between the center and the corner. For you pixel peepers, you can see that the edge is no too shabby at f2. The far corner is not as sharp as the center, but is very respectable. Stopping down to f8/f11 does improve quite a bit, but still not as sharp as the center.
I don't mind the vignette at all. In fact, I prefer it. Usually, if you shoot wide open, you want the subject, usually near the middle, to stand out, and the vignette helps in this regard. Besides, it's completely gone by about f5.6.
Is this why people pay more money for a Pancolar than say, a Pentacon 50mm f1.8? I know the Pentacon 50mm f1.8 does not render pictures like this. The signature is certainly unique for this Pancolar.
Bokeh - Canon 5D Mark II & CZJ Pancolar 50mm f2. Click for larger.
Reflection - Canon 5D Mark II & CZJ Pancolar 50mm f2 @ f11. Click for larger.
100% Crop sample. Need to click on the image to see the actual pixels. You can see that vignetting is pretty sever. I would say it's a difference of at least 1.5 stop.