He must be joking, my arm is still aching since I tried to lift the Sigma, and by all accounts its IQ suffers with extenders. I have taken 1000s of bird photos at 600mm with the 300 II + 2xTC III. But, here is my grandson playing cricket taken with the 300mm II +1.4xTC III on the 5DIII (100% crop). I cannot think of a greater pleasure than the 300mm III, a grandson and cricket.
It looks like my 135L at f2.2
My American express card is burning last couple years with Canon L lenses and 5D III bodies.
Perfect - I have a British Airways American Express card, and the Avios (mileage) points for all the purchases paid for flights for my wife to South Africa and Brazil for wild-life/bird photography. Happy you, happy wife, more glass!
5D IV, 5DS R, 7D II, EOS-M, Powershot G3 X, 400mm DO II, 300/2.8 II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 70-200/4 IS, EF 24-105, 15-85, 100-400 II, Sigma 10-20, Sigma 150-600mm C, EOS-M5 15-45, f/2 22, 11-22, Samyang 8mm f/2.8 fisheye