http://en.wikipedia.org/wiki/Film_director

A film director is a person who directs the making of a film.[1] A film director visualizes the script, controlling a film's artistic and dramatic aspects, while guiding the technical crew and actors in the fulfillment of his or her vision.

However, directors do not always have absolute artistic control. The director is usually selected by the producer, whose job it is to make the decisions that are in the best interests of the production company or studio or network. As such, the producers have veto power over everything from the script itself to the final cut of the film, often in anywhere from slight to extreme opposition to the director's vision.

People such as Anthony Minghella and Paul Greengrass, like Ken Loach and Mike Leigh before them, achieved much of their fame after leaving TV to make films for the big screen. Those directors who choose or are chosen to work in TV traditionally have had to accept that they will not be as lauded, and definitely will not be as well paid, as their big-screen counterparts.[2]

Responsibilities
The role of a film director in the creation of a movie is a large one, and typically includes completion of the following tasks:
• Realizing the overall artistic vision of the film.
• Controlling the content and flow of the film's plot.
• overseeing the performances of actors.

Often directors choose to delegate many of these responsibilities to other members of their film crews. For example, the director may describe the atmosphere he wants from a scene, then leave it to other members of the film crew to find a suitable location and/or to set up the appropriate lighting.

http://en.wikipedia.org/wiki/Film_crew

• Production Manager
The production manager supervises the physical aspects of the production (not the creative aspects) including personnel, technology, budget, and scheduling. It is the production manager's responsibility to make sure the filming stays on schedule and within its budget. The PM also helps manage the day-to-day budget by managing operating costs such as salaries, production costs, and everyday equipment rental costs. The PM often works under the supervision of a line producer and directly supervises the Production Coordinator.

• Unit Manager
The unit manager fulfills the same role as the production manager but for secondary "unit" shooting. In some functional structures, the unit manager subsumes the role of the Transport Coordinator.

• Production Coordinator
The Production Coordinator is the information nexus of the production, responsible for organizing all the logistics from hiring crew, renting equipment, and booking talent. The PC is an integral part of film production.