I had two years a 10-20, 4.0-5.6 Sigma with which I was really pleased. Now I was low on the Canon and can only say that it depicts sharper in direct comparison with my Sigma in the lower diaphragm areas. Once you reach aperture 8 the two lenses give nothing but including Canon's there better. The only thing that is really stupid, is the lens hood. This is very large and you really have problems to accommodate the lens backwards aufmontiertet lens hood in a pocket or backpack. The aperture of the Sigma is much smaller and about the Canon oval and too big in diameter. Whether these oversize better protects against blinding light side I dare to doubt because I've never had problems with the Sigma and the lens hood. But you can not blame the lens and therefore 5 points for the lens and the lens hood only gets 3 point.
