Cinematography is an art that developed from photography, the Greek-derived word literally meaning "to write movement". This emphasises the crucial difference between photography and cinematography, as the latter not only records the image itself, but also any movement associated with it, whether the object being filmed, the camera itself, or both.

The cinematographer is therefore one of the most essential parts of a filmmaking team. Aside from a handful of avant-garde experiments involving painting or etching directly onto celluloid, all films need a cinematographer in a way that they don't necessarily need a scriptwriter (the film could simply record actual events), production designer (the film could be shot entirely in existing locations), editor (the film could be shot in one take or edited in camera) or composer (the film could have no music).

The cinematographer (often credited as the director of photography) is ultimately responsible for the physical process of recording moving images onto celluloid or videotape, but the actual function varies from project to project. At the simplest end of the scale, the cinematographer may single-handedly perform every function from arranging the lights to loading, operating, focusing and moving the camera. On a larger production, the cinematographer may primarily be responsible for the lighting, with the camera operator, focus puller and other assistants physically handling the camera. The cinematographer may also be extensively involved in the film's post-production, particularly when it comes to supervising processing and printing and ensuring that special effects match existing footage.

This BFI Screenonline tour offers a brief history of British cinematography and examples of the work of its most important practitioners. It also examines how technological developments (colour, wider screens, better lenses, smaller cameras) have influenced cinematography from an artistic point of view.