On a recent fall afternoon in Yellowstone, a Bull Bison relaxed in the sunshine to chew his cud and ruminate on his day. My new Nikkor Z600mm PF brought me closer letting me fill the frame with him all without jeopardizing the National Park Service rules to maintain a required 25 yard distance from these beasts. I didn’t even need a teleconverter. It was the first day I’d used the lens, receiving it only the day before leaving for Yellowstone. It proved itself immediately. It is now my favorite wildlife lens.