Just got this lens a couple weeks ago to compliment my 600II and hopefully mostly retire my 100-400. These shots are from the Yukon Wildlife Preserve near Whitehorse, Yukon Canada. The sheep is bare lens, the arctic foxes and the Canadian lynx are with the 1.4IIITC and the Caribou is with the 2.0IIITC. All shot handheld.
Great shots; It seems you could get very close to get these shots.
5D3, 16-35LII, 24-70 2.8LII, 24-105L, 85LII, 70-200 2.8LII, 100L, 135L, 100-400L, 50 1.4, 40 2.8, Sigma 180 3.5 EX, 1.4x TC III, 600EX, 550EX