While observing on Kitt Peak, I get to watch a number of different types of birds flying overhead. Big ones love to make use of the updrafts and some play around with the domes, flying close by them while playing with their friends. This time of year, the Turkey Vultures are quite common and often fly pretty close. Here is one that I caught a few days ago with my 70-200mm f/2.8L IS II on my Canon 70D with an exposure of 1/8000 seconds at f/8, ISO 1600 at 200mm focal length. I normally wouldn't shoot in broad daylight with ISO 1600, but I had used the camera that morning in twilight for some shots of domes and didn't have much time to think about my cameras ISO setting when I saw the birds flying relatively close by. On the other hand, 1/8000 seconds sure does stop the bird and the cameras motion. I love how sharp the images are with this lens - you can see details in the birds eye despite his being at least 100 feet away when I captured this shot. I cropped this from the original frame.