The 180 degree rule states that the camera must remain on the same side of an imaginary line drawn perpendicular to the viewpoint established in the establishing shot. Breaking this rule will confuse audiences as it shifts characters' eye lines and sense of orientation. The only acceptable reason to break the rule is for a specific creative effect. Maintaining the rule ensures continuity and that the audience can follow what is happening on screen.

1. THE 180 DEGREE RULE

2. The ruleThe rule states that the camera(s) should remain the same side of an imaginary lineThe line is drawn perpendicular the camera’s viewpoint in the establishing shot of the sceneThe rule enforces continuity of the filmAn example is that in a car chase scene, if the car is travelling from right to left, the next shot must also be shot from the same side, meaning the car has to enter the frame right to left againThe same applies for football matches and other sport

3. Never break the ruleThe rule should never be brokenOnly defence for breaking the rule is ‘for effect’Breaking the rule will confuse the audience, especially in scenes of chase, conversation or sportCamera must always be on one side of the lineThis is an example of the rule being obeyed

4. Eye lineCrossing the line when filming over the shoulder shots shifts the person’s eye line, meaning that the actors’ eye lines do not matchThe two people should always be on the same side of frame in each shotAs seen below, crossing the line makes it look like the actor is looking in the opposite direction

5. Eye line

6. Results of breaking the ruleConfusion of audienceAudience lose focusBecome disorientatedMiss vital parts of the film

7. Ways around the ruleThe only way to cross the line without disorientating the audience is to show the camera movementYou cannot cut across the line or the viewer will not be orientatedOnce the line has been crossed, and movement shown, you have to stay on that side of the line, unless you show the movement back over it

8. Video exampleThis clip shows a violation of the rule used for effectThe effect created is that of a shot/reverse/shot, but really, the subject is just one character

9. Shot/reverse/shotThis is a film technique whereby one character is shown looking at another off-screen characterThe camera then cuts to the second character looking back at the firstThe characters are shown facing opposite directions, so the audience assume they are looking at each other

10. Match on actionThis is a film technique used to ensure continuityIt allows two different views of an action, without distorting continuityFor example, if you film a person throwing a ball in the air, you can then cut and film it from a different angle, making sure that the arm is in the same stage of motion at the beginning of the second shot as it was at the end of the first shot