Ansel Adams (February 20, 1902 - April 22, 1984) was an American photographer, known for his black and white photographs of the California's Yosemite Valley.
Adams was also the author of numerous books about photography, including his trilogy of technical instruction manuals (The Camera, The Negative and The Print). He co-founded the photographic association Group f/64 along with other masters like Edward Weston, Willard Van Dyke, Imogen Cunningham and others.
He invented the zone system, a technique which allows photographers to translate the light they see into specific densities on negatives and paper, thus giving them better control over finished photographs. Adams also pioneered the idea of visualization (which he often called 'previsualization', though he later acknowledged that term to be a redundancy) of the finished print based upon the measured light values in the scene being photographed.