180 Degree Rule

Crossing the Line:

Screen direction refers to the direction subjects are facing as we look at them in the viewfinder, television monitor, or movie screen. The 180° rule is a cinematography guideline that states that two characters in a scene should maintain the same left/ left relationship to one another. When shooting two people in a scene using three cameras or the single camera master shot, you need to avoid accidentally reversing the screen direction of the subjects when cutting a master shot to a cross shot. A cross shot should have the subject facing the same direction which means the camera(s) should not be switched during live filming. The axis of action, or simple the line, helps keep viewers comfortable by establishing where people are in the scene.