A camera movement along the camera z-axis, toward or away from the subject.
Usage: "Dolly in", "Dolly out".
Refers to a wheeled cart to which the camera is mounted. Replaced in almost all video production by the smooth-operating power zoom lens. However, zooms and dollys look and feel different. Combine both in opposite directions for the Vertigo Effect.
The term can also refer to any motion parallel to or around the subject, though this is more properly known as a truck, also managed at one time with a camera mounted on a wheeled cart running along a small railroad-style track. Today, many of these shots are handled with a Steadicam instead, but there are still uses for the traditional tracked dolly.
Compare Pan, horizontally rotating the camera to get a grasp of the panorama. See also Orbital Shot. Super-Trope of Unimpressive Progress Reveal. Contrast Zoom, the same effect but accomplished by changing the camera's focal lenght.