Years ago, Jerry Lewis (yes, that Jerry Lewis) created the “video tap,” a video camera connected to the film camera by a beam splitter, so he could watch his own performance on a video monitor. This became pretty standard equipment on film and television shows,  even for directors who weren’t appearing in their own films. This has become especially easy since the advent of digital photography, because it’s just an extra video port on the camera.

All of this video is sent to a very large monitor somewhere off set (or at least off-camera). On shows with multiple cameras, there’s usually multiple monitors. People who want to see what’s going on camera gather around the monitors: the director (obviously), script supervisor, producers, other actors, hair and make-up artists (to check the actors’ looks).

The props department generally provides chairs for all of these people, too. When all is said and done, this gathering of people will take up a significant chunk of stage space. Almost like a village surrounding the video monitors…