This little baboon baby had been born hours earlier during the night in the Masai Mara National Park in Kenya. The driver pulled our Land Rover up to the two animals about 8 feet away. I looked through my 70-200mm telephoto and realized they would be too small in the frame, even at this distance. There would be too much dirt surrounding them. I switched to a Canon 500mm f/4 telephoto, but the animals were too close to focus. All lenses have a minimum focusing distance. For the 500mm, that's about 12 feet. So, I put one extension tube between the lens and the body, and that allowed me to focus on the baboons. The baby was constantly squirming in the mother's arms, and I waited until I could capture this tender moment between them. My settings were 1/320, f/4.5, and 200 ISO. Notice that both animals are sharp despite the large lens aperture and the long lens. That occurred because the two heads were on the same plane -- i.e., equidistant to the camera.