While traveling through the Lamar Valley of Yellowstone, we came upon a group of 4 young bull elks grazing near the road. We pulled to the side of the road in typical Yellowstone fashion and used our car as a blind. The elk were completely unaffected by our presence, largely because we did not leave our vehicle and this one came to within 10 feet of us.

This photo is full-frame (not cropped), taken from about 10 feet away, Be silent, keep movements to an absolute minimum and wonderful things can happen.

Canon EOS 5D, Canon 100-400mm f/4.5/5.6L IS @ 400mm, 1/250 sec @f/6.3, ISO equiv 400, stabilized by beanbag on car window