Hi, I've a well used 17-55 which has ldeveloped the following issue:
When IS is on, the image vibrates up and down violently for about 5 secs when the shutter is half pressed. The problem goes away when the lens is zoomed to 50-55mm, but happens at all other focal lengths.
I can use the lens OK with IS off. I cleaned the contacts, but it looks like an expensive repair.
Anyone seen this sort of problem before?