Hippo portrait

I photographed this hippo in Chobe National Park, Botswana. More people die in Africa from hippos attacks than from any other animal, so it's a bit intimidating when a 9000 pound brute looks at you in the eye. He was probably thinking, "I'm letting you live, but don't push your luck!" My Land Rover was parked a safe distance away, presumably, and that's why I had to use a Canon 500mm f/4 telephoto in conjunction with a 1.4x teleconverter. 700mm of focal length filled the frame with the huge head which is what I wanted. My settings were 1/800, f/10, and 640 ISO. With such a long lens, I feel you should use an aperture at least this small (if you have enough light) to recover some of the depth of field lost due to all of that glass.