The 180 Degree Rule

 

What is the rule?

To keep it simple, the 180 Degree rule is an invisible line between two subjects, often used during a conversation, which limits where the camera is allowed to be placed. The camera can only be placed on one side of the line and can not cross over unless the crossing takes place withing a single shot. In this diagram the camera is placed on the green side and the red side is out of bounds but it can be the other way around if required.
 
 
 
 
 
 
 

Breaking the rule

Breaking the rule is rare but can be used quite effectively. For example in this video from the film The Shining