Even after upgrade to latest firmware, AF could not get confirmation on outer AF points on my CANON EOS 1D line DSLR Body. Even after using central focus points the lens sent focus confirmation when there was strong FF/BF - making image worthless with lens set between f/1.4 - f/3.2. Solid build quality, but would recommend only to people that would like to work in manual focus mode and want to use only their eye as focus confirmation.
I must say.. Best in this budget... Very sharp. Very satisfied with the seller very good packaging.