HI! New to SLR. Got myself a Canon 30D two months back. I have the 17-85 IS f4-5.6 and the 50mm f1.8 now.
Now looking to get the 70-200 zoom. APart from the obvious less expensive and lighter that the f4 lense got over the f2.8, what other differentiation points are there that would make one stand out more than the other? So I am like confused now..like do i need f2.8 if i have a flash, is the 2.8 depth of field significant enough? etc..Also thought about 135mm f2 but thought i can kinda get that range with the f2.8. So, appreciate any advice you guys can give assuming that the f2.8 weight and cost is not an issue.