Noob Question Of The Day

This would be a film camera that doesn't record sound. MOS=Minus Optical Sound (or Mit Out Sound). Sound can be recorded on the side of a strip of film optically (lowish quality though). I'm sure I'll get corrected if I got this wrong.

Let's revise that definition, since no film cameras record sound on film nowadays except some 40 year old Auricons. "MOS" refers to a scene that is shot without sync sound being recorded. The term comes from Fritz Lang's Hollywood days, when he'd call for a take "Mit Out Sound". The film slate is not clapped in a MOS shot, merely held up to the camera's field of view for documenting the shot. A typical MOS shot would be a closeup cutaway, enabling an editor to join 2 master shots without causing a jump cut.

Perhaps you're wondering about the difference between a "silent" camera and a "sound" camera. A silent camera is noisy, and a sound camera is not. Got that? The sound camera is built so that the mechanical noise of the camera is so low it isn't picked up by the microphones on set; very necessary for dialog scenes. But silent cameras have their place, such as music videos, where the audio is replaced entirely.

^^^ right.

Usually an "MOS" camera is as said above, but what it really translates to is that they are telling you it's NOISY....When film runs through it, it will be too loud to record good audio.