I just offer me this objective aspect and from the other reviews I liked very much. result my canon 40D not worked for the implementation of this objective: Error 99 !! I had a picture a few seconds with my Canon 17-85mm worry, I put the tamron and that's the end. Apparently there would be a concern of the connectors of the lens with the case. I handed my gun objective but nothing, it is really panne.Je'm really disappointed!