Director of Photography
On a motion picture set the person in charge of the lighting and camera crew is the Director of Photography (or Cinematographer). Sometimes this person is just overseeing the camera operator and sometimes he is operating the camera himself. The term DP or Cinematographer are used interchangeably in most cases. Sometimes people will get snooty and not consider someone a true cinematographer unless he is also the camera operator.
The documentary Visions of Light is a great program detailing the history of the profession. Here is the beginning clip to the show:
If you ever get a chance, you should take time to watch the whole program.
If you want to be a DP, what do you have to do? Well first you have to realize that this is not an entry level position. It takes years to get good at camera and lighting technique. I would suggest learning about the field either through formal training or teaching yourself and then getting involved in productions. The best way to learn about shooting is to get on a set and see how it is done. Going to film school is a good thing in that you get an introduction to the field and make some contacts with others, but you don’t really start your education until you are actually doing the work. Start at the bottom, work as hard as you can, learn from everyone you meet, and keep doing it. It is a life long education that only a handful have mastered.
Additional Information: Wikipedia Cinematographer, The American Society of Cinematographers, Cinematography.com