Review: "L-series professional f/1.4 wide-angle lens with an Aspherical lens element to correct aberrations. The floating system enables high picture quality to be obtained over the entire focusing range. Autofocusing is quick and quiet with rear focusing and ring USM. Full-time manual focusing is also possible.
This isn't a cheap lens, so it should probably come as no surprise that it's performance on sub-frame cameras is really stellar. Even wide open (which at f/1.4 is very wide indeed), this lens is only slightly soft, and only slightly more so in the corners, rapidly improving as you stop down."
