Group f/64 was a group of photographers espousing a common philosophy. The group was created in 1932. The original membership consisted of:
Ansel Adams
Imogen Cunningham
Willard Van Dyke
John Paul Edwards
Consuelo Kanaga
Alma Lavenson
Preston Holder
Sonia Noskowiak
Henry Swift
Edward Weston
The term f/64 refers to the smallest aperture setting on a large format camera, which secures maximum depth of field, rendering a photograph evenly sharp from foreground to background. Such a small aperture implies a long exposure and the selection of relatively slow moving or motionless subject matter, such as landscapes and still life over action and reportage photography.

This corresponds to the ideal of straight photography which the group espoused in response to the pictorialist methods that were in fashion at the time.

Group f/64 published the following manifesto:
The name of this Group is derived from a diaphragm number of the photographic lens. It signifies to a large extent the qualities of clearness and definition of the photographic image which is an important element in the work of members of this Group.
The chief object of the Group is to present in frequent shows what it considers the best contemporary photography of the West; in addition to the showing of the work of its members, it will include prints from other photographers who evidence tendencies in their work similar to that of the Group.
Group f/64 is not pretending to cover the entire spectrum of photography or to indicate through its selection of members any deprecating opinion of the photographers who are not included in its shows. There are great number of serious workers in photography whose style and technique does not relate to the metier of the Group.
Group f/64 limits its members and invitational names to those workers who are striving to define photography as an art form by simple and direct presentation through purely photographic methods. The Group will show no work at any time that does not conform to its standards of pure photography. Pure photography is defined as possessing no qualities of technique, composition or idea, derivative of any other art form. The production of the "Pictorialist," on the other hand, indicates a devotion to principles of art which are directly related to painting and the graphic arts.
The members of Group f/64 believe that photography, as an art form, must develop along lines defined by the actualities and limitations of the photographic medium, and must always remain independent of ideological conventions of art and aesthetics that are reminiscent of a period and culture antedating the growth of the medium itself.
The Group will appreciate information regarding any serious work in photography that has escaped its attention, and is favorable towards establishing itself as a Forum of Modern Photography.