With the smaller sensor, the Wollensak 50mm f1.5 Raptar looks quite a bit better at the corners, but it also loses some of its charms - the blurred corners and vignettes. I have noticed that the G1 has very strong colours, particularly on red, whereas the NEX-5N has more neutral colours. This can be good or bad depending on your preference. Doesn't bother me. I can always dial it down during RAW conversion.
The Wollensak 50mm f1.5 remains one of my current favourite c-mount lenses, but I prefer it on the NEX-5N better than the Panasonic. The lens shows more character on a larger sensor. Regardless, it's a very sharp lens but at the same time renders pleasing colour tones. A little long on M4/3 but still nice.
At the street corner - Panasonic G1 & Wollensak Raptar 50mm f1.5. Click for larger
Mean looking Eagle - Panasonic G1 & Wollensak Raptar 50mm f1.5. Click for larger
Yellow Peppers - Panasonic G1 & Wollensak Raptar 50mm f1.5. Click for larger
Nick Nack - Panasonic G1 & Wollensak Raptar 50mm f1.5. Click for larger