Uhm, it seems that part of this thread disappeared durning the Painful Server is Down Day... So i'm writing this to summarize the latest posts. We were debating about the next lens for my 7D, a telephoto zoom lens. We found, thanks to a very useful Internet page ( http://www.bobatkins.com/photography...d_of_view.html , credits to neuroanatomist for sharing this link), that I need a 400mm lens to frame more or less 3x2 metres being the subject 50 metres away. Being that the focal length I need, the 70-200s are out of the competition. The 100-400 seems to be the right lens for what I plan to do (catching single persons running outdoors during te day, being the worst light condition a cloudy late afternoon). I was wondering if are there alternatives, such as the Sigma 50-500 which was renewed lately. From what I understand, the Sigma has a wider range, but image quality is not as good. The Sigma would also fill the 55-100mm gap I have from my 17-55 (by the way, the 17-55 is as good as a lens can be... did I say that already?), but i's not a critical importance gap for my puropses - I can use the 17-55 @ 55mm and move closer, or ask the subject to come closer, or crop. Do other options exist than the 100-400 and the Bigma? What would you suggest? Thanks!


(Edited for grammar, and for credits to the fellow forum user which found the FOV calculator)