acting for cameras is completely different than acting on a stage.
the set is strange and incomplete and there is no audience. there's no audience, and therefore all the basic rules of blocking and projecting are changed.

the director tells me to move up a foot, stand right in front of him, and all my stage instincts scream. i can't stand there, i'll be blocking him, the audience --

watching the first take, i think that i should have held myself differently, turned more to the left, you can't see my face...and then they switch to camera two, and it turns out i was standing perfectly.

strange stuff.