A cinematographer or director of photography (sometimes shortened to DP or DOP) is the chief over the camera and light crews working on a film, television production or other live action piece and is responsible for making artistic and technical decisions related to the image. The study and practice of this field is referred to as cinematography.
The cinematographer selects the camera, film stock, lenses, filters, etc., to realize the scene in accordance with the intentions of the director. Relations between the cinematographer and director vary; in some instances the director will allow the cinematographer complete independence; in others, the director allows little to none, even going so far as to specify exact camera placement and lens selection. Such a level of involvement is not common once the director and cinematographer have become comfortable with each other; the director will typically convey to the cinematographer what is wanted from a scene visually, and allow the cinematographer latitude in achieving that effect.
In the infancy of motion pictures, the cinematographer was usually also the director and the person physically handling the camera. As the art form and technology evolved, a separation between director and camera operator emerged. With the advent of artificial lighting and faster (more light sensitive) film stocks, in addition to technological advancements in optics, the technical aspects of cinematography necessitated a specialist in that area.
Cinematography was key during the silent movie era; with no sound apart from background music and no dialogue, the films depended on lighting, acting, and set.
In 1919 Hollywood, the then-new motion picture capital of the world, one of the first (and still existing) trade societies was formed: the American Society of Cinematographers (ASC), which stood to recognize the cinematographer's contribution to the art and science of motion picture making. Similar trade associations have been established in other countries too.