For wildlife shooting this is my pride and joy. Fast focusing and incredibly sharp wide open at f/4 or with a 1.4 TC shooting at 700mm f/5.6.
In the never-ending debate on the best lens for wildlife and birds – I chose the 500 f/4. Its significantly lighter than the 600 f/4 or 400 f/2.8, the 400mm f/4 is too short on focal length and the 800 is too long on focal length (there are many times when 500mm is all the focal length I need).
I shoot mine with the Gitzo G-1227 carbon fiber tripod, Arcratech ball head with a Wimberly side-kick. This makes for a lightweight easy to manage and transport set-up.
Here are a few pictures taken primarily wide open at 500mm or 700mm.