What we call the motion picture as distinguished from the still picture might better be called the progressive picture as distinguished from the arrested picture. It is not characterized by "motion" so much as by change of structure in the optic array. And the ordinary picture is not so much "still" as it is stopped.
The progressive picture yields something closer to natural visual perception than does the arrested picture. The nameless transformations that constitute it and that are so hard to describe are actually easier to perceive than the familiar frozen forms of the painting or photograph.
It provides a changing optic array of limited scope to a point of observation in front of the picture, an array that makes information available to a viewer at the point of observation. This delimited array is analogous to the temporary field of view of a human observer in a natural environment surrounding the observer.
The information in the display can specify the turning of one's head, the act of approaching or withdrawing, and the adopting of a new point of observation, although one is all the time aware of holding still and looking at a screen from a fixed position in a room. This is over and above the information in the display for an awareness of events and the places at which the events are happening, along with an awareness of the objects, persons, or creatures of the imagination to which the events are happening. The invariants to specify the places, objects, and persons emerge more clearly in the transforming array than they would in a frozen array.
The art of film-editing should be guided by knowledge of how events and the progress of events are naturally perceived. The composing of a film is not analogous to the composing of a painting. The sequential nesting of subordinate events into superordinate events is crucial. The transitions should be psychologically meaningful, and the sequential order of happenings should be intelligible. But the picture theory of vision and the stimulus sequence theory of perception are very poor guides to movie- making. The theory of ecological perception, of perception while moving around and looking around the environment, is better. The various kinds of filmic transition-- zoom, dolly, pan, cut, fade, wipe, dissolve, and split-screen shot--could usefully be evaluated in the light of ecological optics instead of the snapshot optics that is currently accepted.