The camera's aperture is also called f-stop or focal stop.
The aperture determines how much light enters the camera. It also changes the focal range of the final photograph.
Group f/64 - photography as Art in America
'Pepper' by Edward Weston, 1930
f/64 The modernist group favored sharp focus—f/64 being a very small aperture setting that gives great depth of field, precisely exposed images of natural forms and found objects, and the use of the entire tonal range of a photograph.
In the 1930’s, Adams, Imogen Cunningham, Edward Weston, and others had already leapt into the public debate on the validity of photography as an artistic medium. They founded Group f/64 and wrote a manifesto staking their claim on the definition of “pure photography”.
'Colletia Cruciata 7' by Imogen Cunningham 1929
'Monolith, the Face of Half Dome, Yosemite National Park, 1927' by Ansel Adams
The photo below of the piano keys has a shallow depth the field meaning it was shot with a large aperture. such as f/2.8