Group f/64 or f.64 was a group founded by seven American 20th-century San Francisco Bay Area photographers who shared a common photographic style characterized by sharply focused and carefully framed images seen through a particularly Western (U.S.) viewpoint. In part, they formed in opposition to the pictorialist photographic style that had dominated much of the early 20th century, but moreover, they wanted to promote a new modernist aesthetic that was based on precisely exposed images of natural forms and found objects.

Ansel Easton Adams was an American landscape photographer and environmentalist known for his black-and-white images of the American West. He helped found Group f/64, an association of photographers advocating "pure" photography which favored sharp focus and the use of the full tonal range of a photograph. He and Fred Archer developed a system of image-making called the Zone System, a method of achieving a desired final print through a technical understanding of how the tonal range of an image is the result of choices made in exposure, negative development, and printing.