Looking at upgrading in the telephoto category. currently have a Canon 75-300 f/4-5.6 and i am looking to upgrade to either a Canon 70-200mm f/4L or the Tamron 70-200mm f/2.8 Di LD (IF) Macro. I know the Canon is going to have better quality. but i was curious to see if anyone had used the Tamron. I don't need IS and will be shooting sports, so the faster the better. Sadly the Canon 70-200mm f/2.8 is far out of my price range, the Sigma 70-200mm f/2.8 EX DG HSM II Macro is also another option