30-degree rule

The relationship between 30 degrees and the binocular human experience.

The 30-degree rule is a basic film editing guideline that states the camera should move at least 30 degrees between shots of the same subject occurring in succession. If this rule is not followed, a jump cut occurs which could jar the audience and take them out of the story being told. Instead the audience might focus on the film technique rather than being engaged in the narrative itself.

The 30 degree change of perspective makes two shots in succession different enough to avoid a jump cut. However camera movement should be kept to one side of the subject or action in order to follow the 180-degree rule. Also when thinking about the 30 degree rule it is important to change the shot distance at least 20mm with each move you make on the axis. This would be moving 20mm closer or farther from the subject in reference to the camera distance in the previous camera setup. The 30 degree rule is often referred to as the "20mm/30 degree rule" for this reason. The axial cut incorporates the 20mm idea by moving the camera either closer or father away from the subject without moving on the axis. This type of edit does not follow the 30 degree rule but breaks it in order to obtain a desired effect by the filmmaker. Many filmmakers break conventional rules of film technique in order to achieve desired effects.

The legendary French filmmaker George Méliès, producer of silent black-and-white film, made films before the 30 degree rule existed. George Méliès inspired succeeding filmmakers to heed this rule of angle when cutting between similar or nearly identical clips. When Mèliés himself made his famous A Trip to the Moon (1902) he edited together film clips of the same framing and with the same angle, after changing the scene between the shots, to make it look like there was no cut at all. It was the world's first attempt to make special effects, made up of jump cuts.

As Timothy Corrigan and Patricia White suggest in The Film Experience, "The rule aims to emphasize the motivation for the cut by giving a substantially different view of the action. The transition between two shots less than 30 degrees apart might be perceived as unnecessary or discontinuous--in short, visible." There are some cases where jump cuts are used to show a passage of time or used to achieve an aesthetic style but generally filmmakers try to avoid them otherwise.

The 30 degree rule is a special case of a more general dictum that states that the cut will be jarring if the two shots being cut are so similar that there appears to be a lack of motivation for the cut. In his book In The Blink of an Eye, editor Walter Murch states:

"[We] have difficulty accepting the kind of displacements that are neither subtle nor total: Cutting from a full-figure master shot, for instance, to a slightly tighter shot that frames the actors from the ankles up. The new shot in this case is different enough to signal that something has changed, but not different enough to make us re-evaluate its context."

See also

• film editing
• jump cut
• Continuity editing
• 180-degree rule
• George Méliès
• A Trip to the Moon
• Walter Murch
• axial cut

External links

• "The 30-degree rule", an article explaining the 30-degree rule in depth (showcasing examples and counterexamples from various films).