I have a 5D MkII, 70-200 f/2.8 IS and 1.4X I have been invited to take photos of bears and wolves in a fenced park. I think 200mm, or 280mm with the extender, could be a bit short. I have 2 options within my budget: 1. EF 300 f/4L IS or 2. EOS 7D. I can think of arguments for both options, and it seems a difficult decision. With the 7D I get: 200*1.6*1.4 * 18/21 = 384mm f/4 IS + a new second body. With the 300mm f/4L IS I get: 300*1.4 = 420mm f/5.6 IS, but of FF quality. I now use my good old 20D as a backup body, but it's getting older and older. Other lenses I have: 17-40, 70-200 f/4, 17 TS-E, 24-70, 100 macro What would you do ?