I have been looking into a telephoto lens for Sports, Animals, and a few animals here and there. I've got it down to two lenses. Canon's EF 100-400mm f/4.5-5.6L IS USM and EF 400mm f/5.6L USM. The main reason I'm worried about the EF 100-400mm f/4.5-5.6L IS USM is I have read many reviews of people saying it was hard to get used to. Another is that it seems it looses quality around 400mm. The main reason I'm worried about the EF 400mm f/5.6L USM is the single focal length. I've never used a lens that only had one focal length and I am not sure how I will adjust. I also looked at the EF 300mm f/4L IS USM and the EF 300mm f/2.8L IS USM. Second one needing me to save a little for. But with these I had the same concern as the EF 400mm f/5.6L USM Just some more info... The sports I will most likely being getting photographs of are: Football, Soccer, Volleyball (Indoor), Basketball (Indoor), Few Tennis, Baseball, and Track. So basically most of my high school's sports. Last years annual had horrible, I mean horrible photos in it so I'm trying to fix it so I don't get mad again. Thanks for any help or suggestions.