Field notes

There is no motion on a strip of film. Each frame is a still photograph; the movement is assembled inside you from a rapid run of stills — apparent motion, the phi phenomenon.

Above roughly a dozen frames a second the separate stills fuse into flow. Cinema settled on 24 as the cheap seat just above that cliff — fast enough to fuse, slow enough to afford.

The shutter writes the texture. A wide angle leaves the film exposed while things move, smearing honest motion blur across the frame — the soft, dreamlike look. A narrow angle freezes each instant crisp and staccato.

Sampling can be fooled. When the frame rate lines up with a wheel's spokes, every frame catches them in the same place and the wheel freezes; a touch faster and it rolls backward. Same trick behind a century of Westerns — an alias, not a motion.

The left panel never changes. Everything you do changes only the sampling — and yet motion appears, dies, freezes, reverses.