I just got this lens this week and noticed that the "Whites" tend to be a little over exposed. This is the only lens that I noticed that does this. Is this normal? Or do I have a bad copy! Pictures do come out sharp though. It's just that the "whites' are just a little too much for my liking. I'm using it on an XSi body. I also have a 70-200 "IS" f2.8 and this lens has no problems that I'm describing.