A lot has been said about this lens, it’s even difficult to add something new :) I use this unit for reporting on Kenon 600D. It seems that there is only a 2mm difference with the same whale 17-55mm, but they help out a lot. Especially when shooting in very narrow places (for example, flights of stairs at the ransom of the bride). Good sharpness at f8-11. A very noteworthy lens.