Draco vs. Harry, Ron, and Hermione: A study on placement and lighting.
The actor placement and the lighting are perfect for this shot.
Draco to the left, is separate from Ron, Harry, and Hermione. This is symbolic for their relationship with one another. They don’t like each other in the slightest bit. This goes very well with the events which just led up to this scene. (Draco just ratted out our three main characters).
The lighting is brightest on Ron, Harry, and Hermione’s faces, and dimmer on Draco’s because they are the focus of the discussion.
The only thing standing between Draco and our main three actors is McGonagall (figuratively and literally). She’s standing exactly in between them to show their division.
Professor McGonagall stands the tallest (the 3 are looking up at her), because shes in charge of the scene. We also can’t see her face which makes her more menacing. Not only is McGonagall staring down at our main three characters, but the camera looks down from above as well. This gives us an understanding of the mood of the moment.