I currently have the Canon 400D/Rebel XTi and only the basic 18-55mm lens kit and wanting to add to it. I am trying to decide whether to go for the Sigma 70-300mm lens, (which I can get for about £100), or the Canon 90-300mm lens, (at £122). Does anyone have any opinions of either or experience? I really could go either way, but would generally expect the Canon to be of a better quality. Canon 90-300mm Sigma 70-300mm I am however restricted to about £100-150 at the moment, so if anyone is going to suggest any other lenses as alternatives to both, please bear this in mind. Thanks.