Well my school is planning on getting some new equipment, and I recommended getting a Tele converter for our lenses. We run pretty much all Sigma lenses, well the ones this would be used on are Sigmas, with Canon Bodies. The lenses we would be using this on are a Sigma 70-200mm and Sigma 80-300. It would be used pretty much solely for Golf pictures so that we don't have to stage photos and that we can actually get action shots of golf. So any suggestions on a tele converter to get?