I don't know if this is a common problem, it may be... I have noticed that the sensor from at least two of my nikon cameras has more or less sensibility depending on which side of the sensor is. This is kind of difficult to explain for me because my english is terrible.
The thing is, when I shoot a white background, perfectly illuminated by two flashes or strobes or whatever, always one side of the image get one or two stops darker than the other side of the image, and if I turn the camera to the other side and take the same shoot, the darker side of the image also change, so is very clear that is a sensor problem. I want to clarify that I know how to illuminate a white background. I always use a photometer to get sure that the light is just how I want. I have seen this problem with a D200 and a D800.
Is anybody else with the same issue?, Is this normal?. For how Nikon charge as, it shouldn't.
My lens are all pro line, (24-70 2.8 G ED/N etc. etc...).
If someone has the same issue or know something about this I would really appreciate the info.
thanks a lot y saludos a todos!