Sony NEX-C3 vs NEX-5 Sample 1
bigpen from xitek forums was lucky enough to have the new NEX-C3 and the NEX-5 for a red shift battle. The red shift, vignetting, and / or discoloration is caused by wide angle rangefinder lenses (28mm or less) on the NEX. The light rays from the wide angle lens hit the edges of the NEX sensor at extreme angles since the lens' rear element is so close to the NEX sensor.
The comparison was done with a lens adapter and the Contax G 21mm Rangefinder lens, which is known to produce the red shift on the NEX-5 and NEX-3. It looks like the Sony engineers know of the red shift and has addressed the issue with the new NEX-C3. The 16.2 mp sensor of the NEX-C3 seems to handle the light from problematic lenses in a different way - better. The NEX-C3 samples are the ones on top in each set.
But don't worry, the red shift, vignetting, and / or discoloration can be fixed in post processing by using CornerFix.
The same issue exists for the Leica M8 and M9 and various wide angle lenses. The Kodak sensor in the M9 incorporates micro lenses to deal with the extreme light ray angles.
More NEX-C3 vs NEX-5 samples can be found at xitek.com.
Sony NEX-C3 vs NEX-5 Sample 2
Sony NEX-C3 vs NEX-5 Sample 3