I was in Yellowstone National Park during the bison rut. I watched this bull as he was checking out the cows. At one point he looked in my direction and bellowed. I was aable to shoot with a bean bag on my car window. I had just a second of two before he moved away after a cow. Nikon D300 with Nikon 18-2003.5-5.6 VR. ISO 200, f8 and SS 1/160. Normal photoshop processing and a verticle crop.