We bought this lens twice, and both times it had the same problem with reporting Err 01 (faulty contact with the body) every few shots. None of our other lenses have ever produced this error or had this problem, and it's a well-documented problem with this lens. Canon "repaired" it once, but it came back with the same behavior. The second time we sent it in, they demanded that we also send in the camera body. Very bad service for a pretty expensive lens; the lens has been nothing but a cost to us. Won't buy Canon again. Avoid.