I was at an even with my car club a few weekends ago and I was walking around with my 70-200. Well... I noticed I felt a little wobble between the lens and the body. When I tried to move it by hand, it wouldn't budge (with the little effort I gave it). Then I tried twisting it and noticed that it turns ever so slightly when fully mounted. I took off that lens and put on my 10-20 to see if all lenses do that, and that lens wouldn't move at all. I even had to give it quite a bit more force to get it to turn. Bad copy maybe?