Does anyone know if the 300mm f/4L IS can autofocus with the 2xII converter on the 5D? I've read that the professional bodies can still perform autofocus at the center point. However, I don't know if the 5D is technically "professional" enough to be able to perform this.

A little Googling brought up this page, which is all I could seem to find:

http://photography-on-the.net/forum/showthread.php?t=41922

Under "Requirements for Auto Focus", it lists the 5D as requiring f/5.6 for autofocus. I guess only 1 series bodies can do it at f/8.

Thanks, ekstasis

Your link answered my question clearly. The 5D is grouped with the pro-sumer models and will not auto focus with this combination unlike the EOS Series-1 group.

Thanks for your help. Now I know.