Henri Cartier-Bresson and the Founding of Magnum Photos

In 1947, Henri Cartier-Bresson co-founded Magnum Photos in New York with Robert Capa, David Seymour, and George Rodger. Magnum was a cooperative that allowed photojournalists to own their own negatives — a revolutionary idea at a time when picture agencies controlled both images and assignments.

Cartier-Bresson had built his entire visual practice around the Leica. His concept of "the decisive moment" — the fraction of a second when form, light, and meaning align — depended on a camera that was small, quiet, and fast enough to disappear into a scene. The screw-mount Leica, loaded with 36 frames of 35mm film, was that tool. Its unobtrusive size let Cartier-Bresson work in markets, on street corners, and at political events without the camera becoming a barrier between photographer and subject.

Magnum's founding spread that working method across a generation of photographers. The Leica became synonymous with serious photojournalism and humanist documentary work — an association that outlasted the screw-mount era and carried through to the M-series bodies that followed.