OK. I didn't think this point needed much explaination but it seems I was wrong.
Firstly, like indie just said there are times when things need to be read in from off camera for timing purposes. He gave a perfect example.
Cues for timing in sequences, where that timing is vital to make the action work, and the actors can't cue off each other, can be done verbally or with hand signals.
None of the above instances constitute the director "calling in direction" during a take. In fact, on every set I've ever worked on it's the 1st AD that puts in the verbal cues. Simply because the 1st AD is usually relaying the second cue to the rest of the crew via his/her handset.
But, that's not what we're talking about. We're talking about whether giving an actor direction about performance during a take is good directorial practice or not.
In my opinion it's not. It doesn't get the job done. In fact, I'll go further than that, it's a sign of a poor and egotistical director.
There are very good reasons for this and they are primarily to do with focus and attention. More than any other kind of acting, film acting is about focus. In close ups, in particular, we are so on top of the actor that we are aware of changes in their thinking. If an actor mentally changes their atention from the person in front of them to the sound they hear behind them, even if they don't turn round, we are aware of the shift. This is true of every moment within a piece of drama. Every actor on set is on their own personal journey through the story. Their attention is supposed to be within that world. If you have two characters interacting and the director starts calling in direction then their attention isn't on each other, it is on the director. This changes the quality of the acting from deep inner truth to a superficial puppet show and in film that is immediately obvious.
The other reason that it is bad directorial practice is because actors are part of the creative process and by putting their own interpretation onto a piece they add new dimensions to the story. A good director understands this and keeps quiet, because 99% of the magical moments on screen happen by accident or chance, when an actor trancends the role and does something unexpected. The director's job is to nuture that process and the best way to do that is to shut up, watch and listen. There isn't anything that a director can say to an actor when they're working that can't wait. There is always another take.
Another problem with giving direction during a take is that it is broadcast to everyone on the set and that's just not good practice either, good communication with an actor about their role should be done one to one, away from everyone else. It particularly shouldn't be done within the hearing of other actors on set. They shouldn't be aware of the inner processes of any role but their own.
The problem with many directors is that they have no real understanding of acting as a process or of actors. This leads them to give poor quality direction. Calling in direction during a take is demonstration of poor directorial skills. It leads to bad work. It does not get the job done. It demonstrates a complete lack of understanding of what the job is and I don't care if everyone in Hollywood does it, it is poor practice and no subsititue for real direction.
