I have a Sigma 70-200 f/2.8 that I LOVE. My wide-angle lens selection is limited though (stock 18-55 and a 50mm 1.8) My Goal: to get a full range of 2.8 lenses. (maybe). For instance, a 17-50ish 2.8, and then maybe a 28ish-100ish 2.8. Any ideas on lenses of this range? I currently shoot dirt track races at night--and hope to do sports soon-- so I need as much light as I can get.