Zooming in filmmaking and television production refers to the technique of changing the focal length of a zoom lens (and hence the angle of view) during a shot – this technique is also called a zoom. The technique allows a change from close-up to wide shot (or vice versa) during a shot, giving a cinematographic degree of freedom.
Zooming can either be performed towards longer focal lengths, giving a "zoom in" effect: The filmed object will then increase in apparent size, and fewer objects become visible on film. Or it is performed towards shorter focal lengths, giving a "zoom out" effect: The filmed object will shrink in apparent size, and more objects come into view.
The speed of the zoom allows for a further degree of cinematographic freedom. Combined with a dolly camera move it is possible to create the dolly zoom effect.
A noticeable cinematographic example for the use of slow zooms is the 1975 film Barry Lyndon by Stanley Kubrick.