A person near me is selling one used. ( a Canon EF 70-200 2.8 L non-is), now i am in the market for a telephoto lens. But I was going to get the Canon 70-200 4L brand new. My questions are 1) Ok to buy used? I have never done this before and im worried. He has pictures of it and it looks good and he has the original paper work. 2) What would be the going rate for the lens? Remember it is the Non-IS version. thanks for any input.