I am currently using a pair of Canon 1DMKIII bodies, with any combination of my 70-200 2.8 IS, 400 2.8 IS, and 1.4 or 2.0 TCs. I very seldom use my 100-400 (which I may put up for sale soon) anymore as I prefer the extra exercise I get carrying around the extra weight of the 400 monster. Tripods are a must, and sometimes I use a flash either on camera of off to the side somewhere fired remotely.