180 degree rule

The 180 degree rule can be tricky to understand but it is an important rule to remember when filming.

Between the actors is a straight line that divides the scene in half. On one side of the line is the camera and on the other is the background of the scene. In this shot, you would see actor 1 on the left and actor 2 on the right of the screen.


(BACKGROUND OF THE SCENE)


ACTOR 1--------------------------------------ACTOR 2


CAMERA
(somewhere along this line)


If the camera was to cross this line and show the scene from the other side, the actors would appear to be on opposite sides- you would see actor 2 on the left and actor 1 on the right of the screen.


CAMERA
(somewhere along this line)


ACTOR 1------------------------------------ACTOR 2


(BACKGROUND OF THE SCENE)



This would become very confusing as a director and as an audience member because switching from one shot to another would make it look as if the actor had moved places in the scene.
However, as long as you stay on one side of the line throughout a film sequence, you can move within the space. This means that you can move backwards (creating a wider shot) or closer (to film CUs).
Positioning the camera in the middle (as shown above) establishes the entire scene because more of the picture can be seen. The closer that you get to the 180 degree line, 'the more the viewer's point of view resembles the character's' (http://www.solutioneers.net/cinema/axis.htm). This would give the audience a sense of empathy with the character because they are seeing the scene through their eyes.

If done by mistake, breaking the 180 degree rule can confuse and disorientate the viewer. However, some directors make a conscious decision to step over the line. It can be done to disorientate the audience on purpose in a more abstract way (this would not necessarily work in a more naturalistic, linear sequence). Some directors cross the line by filming a shot where the camera moves from one side of the line to the other. As long as this is included, breaking the rule can be effective because we as an audience have seen the camera switch sides, therefore we understand where we are in relation to the scene. This can show us something from another perspective and reveal more of what is taking place. Directors such as Yasujirō Ozu and occasionally Stanley Kubrick sometimes crossed the line and broke the rule, to different effects.