Michael Mann is one of my favourite directors, and Heat is firmly placed on my top ten of all time list, and so I read with great relish this interview with the usually elusive auteur. I thought this answer in particular was fascinating, especially the nugget about working with Pacino:
Listen, there’s something James Joyce wrote that I’ve never forgotten. “Impervious to fear is Rory’s son: he of the prudent soul.” I take prudence to mean preparation. It is prudent to be prepared. When you are really well prepared, you don’t have anxiety. Anxiety is fear of failure. There’s usually a reason. There’s got to be a reason. If, I’ve never done something before and I’m not prepared for it. I would have, should have fear and anxiety. I see it in some actors. The more prepared an actor is, when he’s prepared, two things happen: he’s great to deal with; second, he’s free because he’s confident. When an actor is totally prepared like, Al Pacino learns his dialogue cold two weeks before he shoots it, he never looks at the script the day he’s shooting, so winging it, taking chances, being on a high-wire without a net, he’s right there. I think no fear comes from knowing.
For me, I have no anxiety if I have a solid foundation in preparation — knowing why I’m shooting in a place or why the camera is here, where the furniture is, how characters walk in, why she’s oblivious to a threat, what’s on her mind distracting her and why. Different ways I may talk to an actor to set him up.
Knowing all that, I imagine you don’t have to worry about finding the movie in editing.
You have to find it again, make it be there in editing. Editing is writing with shot film. The mix is the ultimate writing the movie. At the last stage of the sound mix, your grasp of it can be the closest to the way it was when the whole story first occurred to you. It’s now become that, totally. The screenplay is, of course, the genome, but it’s also blueprint, theory about what’s going to work. Shooting is concrete, but it’s also theoretical about what’s going to work in editing. So, did it work? Yeah, this worked. This other day’s shooting that I thought was going to work, guess what? It doesn’t work. How else can I deliver this story point? Or, another story point I felt was critical to the act two curtain? I don’t need it. I don’t like it even if I did need it. I didn’t have to shoot it. So I make annoying discoveries like that.