Pardon my ignorance, but why won't there be an autofocus past f/8? I currently have a 60D, if I set the aperature at F/11 to take a lanscape picture with my Canon f/2.8 17-55mm, will it also not have autofocus?
The AF works with the lens wide open. For about everything other than current 1D bodies, that requires the lens to be f/5.6 or faster. Third party lenses push that to f/6.3... when you set a smaller aperture, that only takes effect when you take the shot. The focus is done wide open (f/2.8 or whatever).
Canon 1D, 300D IR, 450D full spectrum, 600D, 5D2, 7D, EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 70-300L, 100-400L
EF-S 15-85, TS-E 24, MP-E 65, Zeiss 50/2 macro, Sigma 150 macro, 120-300/2.8 OS, Samyang 8mm fisheye