Editing – The 30-degree rule (Part 1)
The 30-degree rule is a very important film editing guideline. It is also perhaps one of the most misunderstood. The ‘rule’ states that if two shots of the same subject are to be edited together and the scale of the shots doesn’t change significantly, the camera should move at least 30 degrees around that subject between those shots in order to avoid a jump cut. Sounds simple, but is that really all there is to it?
The 30-degree rule
What it all boils down to is that the composition of each shot must be sufficiently distinct from each other so that the audience doesn’t think somebody accidentally kicked the camera stand during the take. Here is an example of a jump cut from You Only Live Once (F. Lang, 1937) resulting from non-compliance with the 30-degree rule.
Let’s reformulate the 30-degree rule:
If consecutive shots remain centered on the same subject, then either the shot scale or the viewing axis must significantly change to avoid a jump cut.
Let’s see that in action.
Error #1: The viewing axis doesn’t significantly change
Let’s assume that both the subject and the scale are the same in a series of shots. In that case, the 30-degree rule states that the viewing axis must significantly change (i.e. by more than 30 degrees) to avoid a jump cut. Both subject and shot scale are strictly the same in the following excerpt from Kill Bill Vol. 1 (Q. Tarantino, 2003), but the cut feels jerky because the viewing axis doesn’t change enough to make a difference in terms of composition. Simply put, the second shot doesn’t bring any new meaning, so we refuse it. Conclusion: If neither the subject nor the shot scale change significantly, make sure that the viewing axis is different enough (i.e. more than 30 degrees) to avoid a jump-cut. Besides, cutting to a new shot should always be meaningful.
In the following excerpt from Raiders of the Lost Ark (S. Spielberg, 1981), the subject and shot scale also remain the same in both shots, but the viewing axis changes just enough (i.e. a bit more than 30 degrees) to avoid a jump-cut. In the second example from Battle Royale (K. Fukasaku, 2000), neither the subject nor the scale changes between the shots, but the shift in viewing axis is quite substantial (i.e. around 90 degrees), nothing to worry about. More importantly, it carries a strong feeling that the character’s attention is drawn from a new direction. It makes sense!
Error #2: The shot scale doesn’t significantly change
Ok, let’s assume that a series of shots are centered on the same subject, and the viewing axis doesn’t change much (i.e. by less than 30 degrees). In that case, the 30-degree rule states that the scale of the shots must significantly change to avoid a jump cut. Indeed, what feels jerky with the following cut from Jurassic Park (S. Spielberg, 1993) is that both shots look too similar in scale. The composition looks the same — character configuration, background, viewing axis. It may look like a cut-in, but the change in scale is too small to avoid a jump cut. Conclusion: If the subject is the same and the viewing axis doesn’t change significantly, make sure that the shot scale changes enough (1 step or more) to avoid a jump cut. Note: You will end up with a regular cut-in or cut-out.
In The Graduate (M. Nichols, 1967), the viewing axis doesn’t dramatically change between those two shots, but a 1-step difference in shot scale seems enough here to avoid a jump-cut (i.e. from a Mid Shot to a Medium Full Shot). In the following excerpt from Kill Bill Vol. 1 (Q. Tarantino, 2003), despite a small change in the viewing axis between the first and second shots, the change in scale is big enough to avoid a jump-cut and look like a cut-out. Note: Conversely, the viewing axis changes enough between the two last shots to avoid a jump-cut, despite similar shot scales.
The 30-degree rule is a very useful guideline when it comes to editing different shots of the same subject together. Changing the scale or the viewing axis from shot to shot makes for different compositions which are more likely to fit together — as long as their occurences make sense in the story.
But the rule has its pitfalls. In part 2, we will see that the most common mistake lies in the subject itself. Moreover, the 30-degree rule sometimes falls short of its objective. And there are times when you don’t want to avoid jump cuts anyway.
- Editing – The 30-degree rule (Part 2)
- Editing – Multiple angles of the same subject
- Editing – Jump cut
- Scaling up – Cut in
- Scaling down – Cut out
- Repetition – Portrait galleries and evocations
- The descriptive power of shot scale