Hi, I am buying a Rebel XTi soon. I need advice on a lens for it. The camera will be used for indoor and outdoor shots. This is a family used camera. My daughter is in gymnastics and we want to photograph her meets. The gyms tend to have low lighting and the events are usually about 50 - 100 feet away from the seats. I am looking to buy a lens that will be good for taking pictures at some distance with not so great lighting. I appreciate any help with this decision. Thank you

