need wider lens for 50D
Looking to get some wider lens for my 50D (widest I have now is 28-135 kit lens). Thinking of either the 17-55, but also thinking I could get the Sigma 8-16 (or Canon 10-22) as well as Canon 28 1.8 (or sigma 30 1.4) for about the same money. Mostly looking for the wide end up to 30MM. Any thoughts from those having used all of these?