A wig-wag (also wigwag, wig wag) is the red light (also known as a "red-eye") near each door of a motion picture

sound stage A sound stage (also written soundstage) is a soundproof, large structure, building, or room with large doors and high ceilings, used for the production of theatrical film-making and television productions, usually located on a secured movie or ...

. It flashes to indicate that

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

s are rolling inside the stage and no one should enter or exit the stage for any reason, and all people and vehicles outside should remain quiet. A flashing wig-wag is accompanied by one long

buzzer A buzzer or beeper is an audio signaling device, which may be mechanical, electromechanical, or piezoelectric (''piezo'' for short). Typical uses of buzzers and beepers include alarm devices, timers, train and confirmation of user input such as a ...

when the cameras start rolling, and two shorter buzzers when cameras stop rolling.

References

Film and video technology {{film-tech-stub