The Decisive Moment
The idea that in any unfolding event there is a single instant at which form and content align most expressively.
In depth
Associated with Henri Cartier-Bresson, whose 1952 book carried the phrase as its English title, the concept links geometry and meaning: the photographer waits until the arrangement of elements and the human action coincide. It has been criticised as privileging elegance over substance, but it remains the founding idea of street photography.
Examples in practice
A leaping figure caught precisely as its reflection completes a shape in the water beneath.