5D2 / 16-35 2.8 Not Autofocusing

Out of my four lenses and two cameras, all combinations work together and focus besides the one in the title. This has not always been the case but during my last wedding it started happening. I cleaned both sets of contacts with an erasure and there is no difference. The round confirmation light in the VF blinks while pressing AF-ON.

Any ideas? Thanks, John

If contacts have been cleaned and the lens doesn't work on any camera, but others lenses do, then the conclusion is it likely needs a trip to Canon or a lens repair specialist. If you feel mechanically inclined there is a YouTube video on how to disassemble. You likely need to replace the ribbon cable,, $9 on ebay.

John from PA wrote in post #16276811
If contacts have been cleaned and the lens doesn't work on any camera, but others lenses do, then the conclusion is it likely needs a trip to Canon or a lens repair specialist.

The lens doesn't work on the 5D2 but works great on the 5D3

I'd suggest cleaning the contacts again, but with a clean cloth and a few drops of isopropyl alcohol (rubbing alcohol).

Often the problem with the contacts is oil... and erasers are made with vegetable oil, so can just make matters worse.

Check that the spring loaded lens contacts in the front of the camera are working properly, too.

If those don't help, I'm afraid you'll have to contact Canon.