That's good info. I saw some of Back to the future again, and I noticed how in the cafeteria scene, most of the master shot, that was used, was from behind Marty's head. I rarely see a shot that goes on for that long, where a character talks that much without seeing his face, but the director made it work, so as long as you can make it work, I guess there are no real rules about how much of the face has to be shown. But I will only do something like that for certain scenes, where the silent character's face, is more important.
So the point of the safety of the master is, to have a take or two, where the actors, successfully act the whole thing out in one shot, right? So I guess this means I should shoot a master on a steadicam, even if it's just a dialogue scene. Cause if the actors go to sit down and stand up, I can move the camera with them, where as a tripod, the tripod bends the camera up or down, causing it to curve. The steadicam has no curve, but rather elevates the camera, so I guess I should use that for masters, where movement is a factor, right?