Ansel Adams (February 20,1902-April 22, 1984) was an American photographer born in San Francisco.
Famous for his black & white landscape photographs of the national parks (Yosemite National Park among others), and as an author of numerous books about photography, including his trilogy of technical instruction manuals (The Camera, The Negative and The Print). Adams was also an environmentalist and a member of the Sierra Club.
He invented the "Zone System" a technique that allows the photographer to translate a visual impression of his or her subject to photographic film and paper. As well as the Zone System, Adams also pioneered the idea of 'pre-visualisation', the idea of seeing a completed print and then working through the steps to build that print.