Post #502349 by bigbrotiki on Mon, Jan 4, 2010 8:59 PM

A popular (presumed to be mythical) origin theory is that MOS stands for broken-English "Mit out sound", that is, "Without sound" as a 1920s German-émigré director might have said it.
According to this theory, a German director, recently transplanted to Hollywood (probably Ernst Lubitsch, but possibly Fritz Lang), was asked by a script supervisor how he would like to shoot the next scene of the day. The director responded "Mit out Sprechen!", and so this was noted as a joke on the production reports and the camera slates for the shot."

And since we are on the film subject: I believe that a well placed spot light, ideally from the top, let's say at a 45 degree angle to the subject, would really bring out its features nicely :D