This is an uncropped photograph of a jaguar swimming right past my boat in the Pantanal region of Brazil. I wanted to switch from my 500mm telephoto to a 100-400mm zoom as the cat came closer and closer, but I didn't have time. By the time I would put the zoom lens on the camera, I feared the opportunity would be lost. So, I shot this with the 500mm telephoto when the jaguar about 12 feet away. My settings were 1/1600, f/8, and 1600 ISO. I now choose shutter speeds that are faster than necessary to err on the side of caution. In other words, I don't want to take a chance that action shots are 'almost' sharp. Nothing in photography is more disappointing than that. When I shot film, 100 ISO was the standard speed I used for wildlife only because 400 ISO was too grainy. In the digital arena at this time, 1600 ISO is no problem at all. What a great time to be a photographer!