What does the black rectangle clipper when filming films and movies actually do? Why do they need one at all?

Question

I always wondered this

In: 133

Answer 1

As others have said, it serves to record scene and take information into the video, and to help sync up audio recorders with the video from cameras. Another thing that hasn’t been mentioned yet is that when the slate is shown to the camera, the assistant holding the slate will read out the information using suitable phonetics (eg “scene 3, take 2, camera A for alpha”) so that it’s embedded in the audio recording as well. If video is recorded with no sound then the slate can be shown without clapping (usually shown by placing a hand in the way of the clapper), also, it could be shown at the end of a take (traditionally upside down), sometimes this is to show a take that has been cut early.