1. prepare the cameras for each scene in a movie
2. discusses the director's vision for the film with him, both overall and scene by scene.
3. works with other departments, like sound and lighting, to coordinate production needs.
4. coordinates the crew and works with the director to make sure each scene is set up and shot to match the director's vision of the story. 
5. run the show, directing the technical production crew 
6. making sure the correct lenses, filters, cranes, Steadicams, dollies, and lights are used for each shot
7. works with the processing lab to make sure the film retains the color and mood that he and the director wanted.