Sunday evening after out taking some photos I was walking up the stairs to my garage apartment. I had my beloved 400mm5.6 on my camera slung over my shoulder and for some reason I had my also beloved 100-400mm in my other arm with some other stuff. I always carry the lens I'm not using in a bag, but somehow I had it out of the bag and carrying it like it didn't cost me $1600 dollars. As you can probably guess as I reached the top step and stumbled, there goes my baby bouncing 3 or 4 times down the stairs before hitting the concrete below. After about 10 minutes sitting on the step staring at it and wondering why I was so stupid I went down to check it out. When I picked it up all seemed well, no broken glass, maybe I got lucky. Nope when I tried to use it, it won't focus. I sent it off to Canon Monday morning and am waiting for the verdict. That's a horrible sight watching your beloved bouncing down the stairs. Terry.