The best glass I've ever tried (Canon glasses, of course). The vertebra of the spine has shifted between the shoulder blades, I make up to 1000 frames per shooting day. I have been using it for the second year since the first review! TOTAL: "plows like a tractor", sharpness at wide angles is not so hot, still not fixed. I begin to understand a lot in the creative community of using this LENS model. Briefly "ABOUT HIM": cunning, cunning, demands that "ON YOU" be with him. The vertebra shifted even more from cooperation with him .