180 Degree Rule Diagram

The 180 Degree rule is a rule used in making Films and anything video based. Its based on the simple principles that in a shot there is a line down the centre of everything. For example in a dialogue scene between two characters there would be a centre line made. Using the 180 degree rule means that the camera must stay on one side of the virtual line you create down the scene. If the camera crossed the centre line it can distract and often confuse the viewer. This can be used to a film makers advantage in a horror film for example where the viewer should be confused.
In the example diagram below there is a clear demonstration of the camera being set behind each of the characters on each side of the centre line. The camera is looking over the shoulder of one of the characters, that is represented by the larger figure. We see the other character over their shoulder, that character is represented by the smaller figure.

180 Degree Rule Diagram