A dolly zoom moves the camera and zooms the lens against it at the same rate, so the subject keeps its size while everything behind it stretches or looms. Hitchcock told Truffaut he had wanted the feeling since Rebecca in 1940, remembered from being terribly drunk at a ball in London. For Vertigo, rigging a camera above real stairs was quoted at $50,000. His fix, in his telling: a miniature stairwell laid on its side, the camera tracking back along the floor while zooming in, for $19,000. Paramount cameraman Irmin Roberts is usually credited with working it out. Jaws turned it on Chief Brody on the beach in 1975.

The rule: the focal length grows with the distance. Three times as far, three times the millimetres, same size.

It is used to mean fear or dizziness. We looked for a study that measured that feeling and found none.

The stairwell, the stand-ins and the lens are our own, built and lit in code.

Did your stomach drop anyway?

Sources: Truffaut, Hitchcock (Simon and Schuster, 1967); Liang et al., CVPR Workshops (2020).
Music: made with ElevenLabs Music. Sounds: made by us; ocean surf by leosalom (Freesound, CC0).