this zoom is in addition to my Canon 55mm objectives fixed opening 1.4 and almost gives me the same result! 17mm wide angle in an excellent result I opened 2.8 mm and used lenses ensure excellent sharpness and color rendering identical to Canon intermediate focal length 24mm there's no image distortion at the edge 50 mm Canon keeps an advantage through its opening 1.4mm, the portraits are deeper
One downside: '' autofocus is slower than the Canon, also to make snapshots I commend my Canon fixed with whom I can shoot with perfect clarity a flying bird that does not allow me the Sigma in any case I can only recommend that goal comes with its visor and padded storage case
