Grammar of the Shot, 2nd Edition

Depth Cues

The combination of foreground, middle ground, and background elements helps create the illusion of three dimensions on the 2D film frame. They accomplish this in a few ways. First, they act like layers. The tree branch in the foreground will partially obscure the elements of the MG and BG. The main action taking place in the MG will obscure visual elements found in the BG zone. So, just like in real life, when objects (static or moving) appear to be in front of one another it allows our brains to establish depth cues. Second, the relative size of a known object will also trigger depth cues. For instance, you may observe a small skyscraper within the shot. Because skyscrapers are known to be very tall buildings, it would make sense ...