I'm taking the ferry over to San Francisco in a couple of hours to look at a Vr 1. The guy I am meeting bought it second hand from a pro photographer about 1.5 years ago. Overall it is 2.5 years old? I posted earlier bout how to evaluate a lens and someone mentioned bringing a strong light and shing it thru and looking for dust fog etc... I tried this on my tamron 17-50. And can't see much.. The perturbed hole is very small... I tried setting it to 2.8 and its still pretty small so I can't see much. He says the lens is in excellent condition. But how do I tell? I am bring my body and 17-50 along and will take some test shots... What to look for? Hopefully 17-50 on the way in and 70-200 on the ferry ride back. .. Help me make sure I do as well as I can.