One way you can pose the question of acting for camera is to say the camera is photographing thought.
It’s pretty good.
As always, none of these truisms are to be taken mechanically. It’s just one way to skin the cat.
Viewers love to see thought in the eyes of the actors and the close-up really allows that to happen.
Set yourself up to be thinking. Let them film you. Keep your breathing lion-like: soft, fat and rhythmical. This will help your mind turn and wander. Get lost. Dream while the camera runs.
Thought makes the eyes move. Naturally. And the eyes are the window to the soul.
The medium of now - film and television - allows us to do something so psychologically intimate that it occasionally makes us gasp. To see someone thinking so deeply in a moving, colour picture on a screen of 20 by 70 feet can be breathtaking.
You might sometimes hear that fearful voice in your head say: ‘I’m not doing enough. Forget it. We love to watch humans thinking. It is an aspect of film and TV acting that is essential. If you’re thinking real thoughts while acting in a scene you will be compelling. And doing enough.
Observe yourself off camera when you’re thinking. Observe others while they are thinking.
You are reproducing recognizable human behaviour.
Thinking is a big part of it.