If I could afford more I would be but I can't so these are my options. Used; Canon ef 55-200mm f/4.5-5.6 USM $210 New; Sigma 70-300 f/4 - 5.6 AF DG macro $220 seen on C'slist $175 New; Canon EF 75-300mm f/4-5.6 III USM $300 seen on craigslist for $200 None are IS so what I'm really looking for is image quality. Which of these is going to be the best? They are all pretty much the same aperture. I'll be using a tripod at longer lengths anyways. I'm on a budget so these are my options. None will be fast so in terms of quality I'm looking for sharpness contrast and color representation.