Cinematography is the act of capturing photographic images in space through the use of a number of controllable elements. These include the quality of the film stock, the manipulation of the camera lens, framing, scale and movement. Some theoreticians and film historians (Bordwell, Thompson) would also include duration, or the length of the shot, but we discuss the long take in our editing page. Cinematography is a function of the relationship between the camera lens and a light source, the focal length of the lens, the camera’s position and its capacity for motion.
Here is a basic introduction including viewing examples that should help you understand the core principles: