"Deep focus is what you need. I crouched in the bushes until my knees ached, hoping for this picture to compose itself," says photographer Chip Clark. "Flamingos feed by dipping their bills into the water and straining out crustaceans and other stuff they love to eat." All those shrimp are why their feathers are pink. The rapid pumping motion of their bills caused the close ripples. Equipment matters, of course. "For this shot, I used a 500-millimeter fluorite lens — a legendary lens, very sharp, superb optics. But it costs $6,000. These birds were wonderfully serene — going about daily life as they have for millennia." An exhibition of Clark's images will be on view at the National Museum of Natural History through September 7.