I currently use the 100-400 on my 7D for a lot of outdoor photography and love the combination. Its very sharp and the versatility is great. If your primary work is sports, more focal length is going to be key. As someone mentioned above, if you're not worried about having the zoom range of the 100-400, then I'd suggest the 400 f/5.6. Its sharper than the 100-400 @ 400 and its a lighter lens. The only downside is you lose IS with the 400 f/5.6. You'll be very happy with either lens.


And even though the 70-300L is supposed to be extremely sharp, I'm personally not a fan of this lens because 300 @ f/5.6 is way to slow, and it overlaps with the already excellent 70-200mm lenses. I just don't understand the point of this lens.





Mike