Quote Originally Posted by neuroanatomist
But to argue the other way[img]/emoticons/emotion-14.gif[/img]the 10-22mm is very, very well-corrected for distortion on the wide end - only 1.2% barrel (in fact, I am occasionally surprised that the excellent EF-S 17-55mm is actually noticeably more distorted at 17mm than the 10-22mm at 10mm). Compare that to either the 17-40mm or the 16-35mm on FF, both of which have well over 3% barrel distortion at the wide end and will give you a smiling or frowning horizon line if you compose it off-center...

The Sigma 12-24 has an even wider view and with less distortion even at 12mm...just saying...there's no such thing as a 7,5mm wide angle for an APS-C body as far as I know...without it beying a fish eye lens [:P]