Formal signal that a scene or setup is complete and camera stops rolling — director calls 'button' when the last shot is locked. Distinct from wrap.
As soon as the camera stops and the director is sure that the shot is in the can — technically and dramatically — they call "Button." This is the formal go-ahead for the next setup. Not to be confused with "Wrap," which signals that the entire shooting day is over. Button is the operational clearance for a scene change, a new angle, a different location. It's the second when the crew knows: we don't need this shot again.
The practice on set is brutal everyday reality. The 1st AD observes whether the director nods or gestures — some directors work with a clear "Button!" exclamation, others give a silent hand signal. The crew immediately springs into action: the camera is taken off the tripod or slider, lighting grips reposition their equipment, script continuity notes, sound documents. The cut between Button and the next slate is pure efficiency. In contrast, "Again!" or "One more!" — then everyone knows the shot was garbage or incomplete.
For us DoPs, Button is also a mental event. You know the lighting for this shot is finished. You can take a breath before the next angle is set up. Sometimes it takes ten takes until Button falls — actor's performance, technical error, or the director suddenly sees that the frame isn't quite right. That's completely normal. Button isn't perfection, but legitimacy: this is usable for the film.
The term itself comes from the practical vocabulary of English-speaking sets and has become international — simple, precise, unmistakable. In German-speaking countries, they sometimes also say "Abschlag" or "Fertig," but "Button" is the standardization that everyone understands. Another thing is "Check the Gate" (formerly necessary with film, now digitally obsolete), which came before Button — but that's a different matter. Button is not quality control, but administrative clearance.