Adams helped found Group f/64, an association of photographers advocating "pure" photography that favored sharp focus and the use of the full tonal range of a photograph. With Fred Archer, he developed an exacting system of image-making called the Zone System, which described a method of achieving a desired final print through a deeply technical understanding of how tonal range is recorded and developed in exposure, negative development, and printing. The resulting clarity and depth of such images characterized his photography. Adams was a life-long advocate for environmental conservation, and his photographic practice was deeply entwined with this advocacy. At age 12, he was given his first camera during his first visit to Yosemite National Park. He developed his early photographic work as a member of the Sierra Club. He was later contracted with the U.S. Department of the Interior to make photographs of U.S. National Parks. For his work and his persistent advocacy, which helped expand the National Park system, he was awarded the Presidential Medal of Freedom in 1980.
