Ansel Adams (San Francisco, California, 1902 – Monterey, California, 1984) turned landscape photography into a language of monumentality, exacting tonal control, and environmental conviction, treating the American West not as scenery to be recorded but as a physical place with a moral claim on the viewer.

His first visit to Yosemite Valley in 1916 began a lifelong attachment, deepened through his work with the Sierra Club, first as a custodian and later as an official expedition photographer. The 1927 photograph Monolith, the Face of Half Dome marked his decisive turn from documentation toward deliberate construction: working from a narrow ledge with only one glass plate left, he fitted a red filter to darken the sky and give the cliff face what he called a "monumental, dark quality," planning the print's full tonal range in his mind before he ever exposed the negative. "This photograph represents my first conscious visualization," he later said of the method that became his defining principle: an image's emotional effect had to be composed in advance, then engineered through exposure and printing, however spontaneous the result might look.

That engineering matured into the Zone System, a method for mapping a scene's full range of light onto a controlled scale of print values, which Adams developed and taught for decades. In 1932, he co-founded Group f/64 with Imogen Cunningham and Edward Weston, advocating for "straight photography": sharp focus, formal discipline, and the medium's independent status as fine art. Adams helped found the Department of Photography at the Museum of Modern Art in 1940 and received three Guggenheim Fellowships. His photographs did not simply record wilderness; through scale, deep foreground detail, and the stark separation of black and white, they built a public imagination of the American landscape as monumental and endangered at once, work recognized in 1980 when President Carter awarded him the Presidential Medal of Freedom. His photographs are held in the collections of the Museum of Modern Art, the National Gallery of Art, and the San Francisco Museum of Modern Art.