Transitions are the most over-applied tool in consumer video editing, and it is not because people have bad taste. It is because the software puts them in a drawer labelled "make this look better", which is not what they do.

What each one actually means

A cut means: next thing. It is invisible, it is instant, and it carries no information beyond "we have moved on". Roughly ninety percent of every edit you have ever watched is cuts.

A transition means: something changed that a cut cannot express. Time passed. We are somewhere else. This section ended and another began.

Two clips on a timeline overlapping, with the overlap marked as the transition.

That is the entire vocabulary. Once you hold it, the question stops being "which transition should I use here" and becomes "is anything actually changing".

The three cases where a cut always wins

Between two takes of the same person in the same chair. This is the big one. You fluffed a line, you said it again, you want to join the good halves. The instinct is to hide the join with a dissolve. What a dissolve says there is "time passed", which is a lie the viewer can see through, because your shoulders are in almost the same place. Use a cut, or cover it with b-roll, or accept it as a jump cut, which is an honest and completely normal thing for a talking head video to contain.

Inside a continuous action. Somebody reaching for a cup, walking through a door, drawing on a whiteboard. A transition inside a continuous motion breaks the continuity it is trying to smooth.

On a rapid sequence. Six quick cuts in four seconds carry their own energy. Putting a transition on each one slows every join by a third of a second and kills exactly the pace you were building.

Where a transition earns its place

Between sections. You have finished explaining the problem and you are moving to the solution. That is a real boundary and a transition marks it.

Between locations. Indoors to outdoors, desk to street. The viewer needs a beat to relocate.

Across a time jump. Before and after, day one and day thirty.

Into and out of the video. A fade from black at the start and to black at the end are transitions doing their oldest job.

Choosing which one

Once you have decided a transition belongs, the choice is narrower than the menu suggests:

Situation Use
Section break, same setting A short dissolve
Scene or location change A fade, or a longer dissolve
Energetic cut in short form A zoom punch or whip
Anything you cannot describe A cut

That last row is the useful one. If you cannot say in words what the transition is telling the viewer, it is decoration, and decoration at a cut point reads as amateur faster than almost anything else.

Letting the software decide

Zella has Auto-Transitions, which analyses each cut on your device and picks per join: a zoom punch on a jump cut, a dissolve when you are still in the same scene, a fade on an actual scene change. It runs on both the Mac and the iPhone.

Two things are worth understanding about that. The first is that it needs cuts to work with, so make your cuts first. The second is that it is applying the rules above rather than replacing them: it is reading whether the scene changed and choosing accordingly, which is exactly what you would do by hand with more patience.

If it puts a transition somewhere you would have cut, delete that one. Being able to disagree with an automatic pass at one specific join is more useful than the pass being right every time.

Duration

Shorter than you think. A dissolve between sections wants somewhere around a third of a second in short form and up to a second in long form. Anything above a second reads as deliberate style and needs to be a choice you are making on purpose throughout, not one long dissolve in an otherwise brisk edit.

The how to add transitions between clips walkthrough covers placing and retiming them.

The test

Watch the video with the transitions and then watch it with all of them removed. Almost always, the second version is tighter and only two or three joins genuinely wanted something.

Put those back. Leave the rest as cuts.

The Final Cut Pro documentation covers the mechanics in a professional context, and its default advice is the same: cut unless you have a reason not to.

Common questions

Should I put a transition between two takes of the same shot? No. A dissolve there says time passed, which the viewer can see is untrue because your shoulders barely moved. Use a cut, cover it with b-roll, or accept the jump cut.

How long should a transition be? Around a third of a second in short form and up to a second in long form. Anything longer becomes a deliberate style you need to carry throughout.

How do I know if a transition is doing anything? Try to say in words what it tells the viewer. If you cannot, it is decoration, and decoration at a cut point reads as amateur faster than almost anything else.