Focus

Seeing through a lens clearly

Focus

A picture is in focus when it appears sharp and clear on-screen

Technically, the point where the light rays refracted by the lens converge).

Rack Focus

To change focus from one object or person closer to the camera to one farther away or vice versa.

Auto Focus

Automated feature whereby the camera focuses on what it senses to be your target object.

Defocus

The camera operator zooms in, racks out of focus, and, on cue, back into focus again.

Used as a transitional device or to indicate strong psychological disturbances or physiological imbalance.