“It’s like the neck of a swan or something like that, if you wanted to pursue that analogy,” Mr. Brown said. “It has reach, and that reach is part of the ballet of dancing around with it. And that goes in combination with where your feet can get you.”

Multiple filmmakers speak of the way the Steadicam combines artistry and athleticism, requiring the camera operator, the crew and the actors to contend with obstacles in their way.

Brian De Palma first used the Steadicam, with Mr. Brown as an operator, in “Blow Out” (1981) for the opening sequence, an elaborate horror movie parody in which a slasher attacks coeds. “Choreographing the shot, getting the psychopath to hold his knife up in front of the mirror at the right time — it was a kind of joyful evening,” Mr. De Palma said by telephone. He went on to use the Steadicam in many films, including “Raising Cain” and “Carlito’s Way,” showing in the Film Society series.

For Mr. Brown, who taught himself filmmaking, movies came after a folk-singing career (as part of the duo Brown & Dana) and a stint selling Volkswagens. He found himself working in commercials at a time when the only way to create smooth camera motion was to put the camera on a dolly, in a camera car or on a crane. He was pained by the unwieldy setup of a 12-pound camera on an 800-pound dolly.