Hello,

I hope that any of you can provide some direction. I was going to use this lens with my 5D Mark II this morning and noticed that the autofocus wasn't working. Checked and double checked my settings and didn't find anything wrong with them. My son has the same 5D Mark II camera body and I tried the lens on his camera. Same result. AF not working. He also has an old 20D so we decided to mount the lens and try it. The AF worked perfectly.

I was thinking that it could be a custom function that I changed without realizing that I was changing something, so I cleared all custom functions. Same result, AF not working. We tried other Canon and non-Canon lenses on both 5D M2 cameras and the AF worked fine with the other lenses.

When I go to the menu, under Peripheral illumin. correct., the camera shows the correct lens attached.

Is it possible that I am missing a setting that makes the AF stop working? The lens was working fine with this camera, and it works fine with my son's 20D. I'm stumped and any suggestions will be greatly appreciated.