Uneven color rendition

Why can’t simple tests be simple? Like checking for uniform color across the frame.

Mouse over the image below. Both variants show color non-uniformity, a fairly common phenomenon with wide angle lenses, and not specific to the Voigtlander 20/3.5 Color-Skopar used here. Symmetry is my expectation, but it’s asymmetric.

One image shows a too-blue right side, and one image shows a too-blue left side. The difference? I shot the first image with the camera right-side-up, and the second one with the camera upside down, to rule out something funny with my target or the lighting. Well, the not so funny business is with the lens and camera!

Nikon D3x + Voigtlander 20/3.5 Color-Skopar @ f/8

Is my D3x sensor still off? It seems not, since the same lens on the Canon 5D Mark II shows the same effect. And so do other lenses! I don’t have a good explanation offhand, but this is why a 30-minute test takes a few hours to shoot and shoot again when oddball findings present themselves. My reviews don’t just test, they teach, because I take the time to present and explain such things.