For more than 40 years, photographer William Wegman has been making portraits and videos of his beloved Weimaraner dogs. They've appeared in countless publications and have been featured on television programs ranging from Sesame Street to Saturday Night Live. This month saw the publication of a new career retrospective book, "William Wegman: Being Human." It features 300 images, some never published before, from his vast collection of prints. NewsHour Weekend's Megan Thompson visited Wegman in his New York City studio, where he introduced us to his top canine models, Flo and Topper.