the mirror scene, and there are many, one trick was the camera came in through the door and followed Michael Keaton as he sat down in front of the mirror, the camera came in facing the left side of the actor. As the camera passed behind his entire head filled the frame. That is where the made the cut then turned the camera looking at the right side of his face so there is a moment when the frame is blacked out. I noticed a lot of this in Birdman, and this is where they would cut the scenes. It was filmed at the St James but only the Stage and backstage. Everything else was contructed and built across the pond in Queens at another soundstage. The Art Director did a remarkable job making these sets look old with half ass renovations done over the years. I have watched the movie 5 times already, they are constantly showing it on Cinemax.