The build quality is impeccable, the handling as usual. The ring-type USM is quick and allows manual corrections, which are rare but necessary. The lens moves minimally but inside the tube, which is in bad weather advantage. Diaphragm and filter rotate accordingly with not.
At first I was skeptical to buy a lens without IS, but in the short focal lengths is not really necessary. Even 1/15 sec. I have sharp shot out of hand.
The picture quality is great, Canon has done a great job at this extreme focal length. CA is visible, from RAW files but are easily eliminated, and the distortion is kept within manageable limits.
The sake of completeness must be said that there is an EF-S lens that does not fit on full-frame cameras. Also, the internal flash of my EOS 7D is not usable, since there are over almost the entire focal length range (10 to 20 mm) away shadows through the lens. Even with an external flash is the only diffuser from 14mm and the back practically only indirectly. That is absolutely correct and of course nothing for which the lens can be something.
As usual, the criticism that the lens hood is not there, but what then is in the price not care.
Conclusion: in the city I will never again without :)
Short afterburner: I see grad, that it is described as a 72mm filter thread. This is wrong, there are 77mm.
