Second copy of this, and used on EOS 7D always the same desire to focus random, imprecise, even after a sharp correction in the housing adjustment ... The sharpness is only 1.4 infamous soup ... it takes close to 6 or 8 to get something acceptable (when it was able to focus ...) and the concern is the same on a 20 D .... So autofocus with collects and missing dive. has avoided