The 180 Degree Rule

One of the most basic continuity rules in producing a dialogue in a film between two people is the 180-degree rule.  This rule states that the two characters being filmed must have the same left/right relationship to each other. If you don’t follow the 180-degree rule, then it disorientates the audience and makes it look as though the actors are facing the opposite way to what they were. It then results in them looking as though they are looking the same way.

This shows how it is done and that the camera can only be on one side of the actor.