This is what Wiki has to say.
A cinematographer or director of photography (sometimes shortened to DP or DOP) is the chief over the camera and lighting crews working on a film, television production or other live action piece and is responsible for achieving artistic and technical decisions related to the image. The study and practice of this field is referred to as cinematography. Some filmmakers say that the cinematographer is just the chief over the camera and lighting, and the Director of Photography is the chief over the all photography components of film, including framing, costumes, makeup, and lighting, and it’s the assistant of the post producer for color correction and grading.
The cinematographer selects the film stock, lens, 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.
Several American cinematographers have become directors, including Barry Sonnenfeld, originally the Coen brothers’ DP; Jan de Bont, cinematographer on films as Die Hard and Basic Instinct, directed Speed and Twister. Recently Wally Pfister, cinematographer on Christopher Nolan‘s three Batman films made his directorial debut with Transcendence.
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.
In 1919, in Hollywood, the 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.
Societies and trade organizations
There are a number of national associations of cinematographers which represent members (irrespective of their official titles) and which are dedicated to the advancement of cinematography. These include:
- the American Society of Cinematographers (A.S.C.)
- the Canadian Society of Cinematographers (C.S.C.)
- the British Society of Cinematographers (B.S.C.)
- the Australian Cinematographers Society (A.C.S.)
- the French Society of Cinematographers (A.F.C.)
- the Italian Society of Cinematographers (A.I.C.)
- the Indian Cinematographers Society (I.C.S.)
- the German Society of Cinematographers (G.S.C.)
The ASC defines cinematography as:
- a creative and interpretive process that culminates in the authorship of an original work of art rather than the simple recording of a physical event. Cinematography is not a subcategory of photography. Rather, photography is but one craft that the cinematographer uses in addition to other physical, organizational, managerial, interpretive and image-manipulating techniques to effect one coherent process.