I appreciate your reply. We have a competition next 11/18. I am thinking about renting a lens. Am looking at the Canon 70-200mm f2.8 is l , or the Sigma 18-200 mm f3.5-6.3 optically stabilized. I know there is a big difference in rental price and the Canon is more than likely better, do you think it is worth the extra money?
Not even close - the two lenses are in completely different categories. Optical quality is going to be much better in the Canon and you have a 2-stop advantage (2.8 vs. 5.6) Of course it is a heavier lens - but the bottom line is the SIgma just isn't going to be up to low light action shots - no 5.6 lens is. The 2.8 will have a tough enough time (usually I have to shoot at iso 3200 to use 2.8 for indoor action).