Owner of a Canon 7D associated with excellent 15-85mm, I needed a zoom bearing further to the animal pictures. What are the negative points? The zoom mechanism a little hard. The rotation direction reversed compared to Canon zooms. More seriously, the focus ring in manual focus almost unusable: 1/4 turn in going from 49 cm to infinity. Also annoying: the autofocus mechanism and stabilization of discrete but still audible and therefore unusable during movies. The POSITIVE points: the zoom range, the overall build quality, compactness and lightness of the lens, the very effective stabilization and autofocus rather fast (but not as fast as my 15-85). Overall an excellent value that will delight photographers who do not intend to make video or proxiphoto. About me, I believe in having my money.