How to make a slow motion video that looks smooth
Smooth slow motion comes from filming at a high frame rate, then playing it back slower: footage shot at 120 fps plays at a quarter speed in a 30 fps video with every frame real. You can also slow down normal 30 fps footage, but every frame then repeats, and below about half speed it visibly stutters unless your editor creates in-between frames (optical flow). Either way, save slow motion for one or two moments and ramp in and out of it. Here's how much you can slow down, how to film for it, and how we used it in a sports highlight.
How slow can you go?
| Filmed at | Played in a 30 fps video | Max smooth slow-down | Notes |
|---|---|---|---|
| 30 fps | 30 fps | ~50%, briefly | Frames repeat; fine for a short ramp, choppy below 50% without frame interpolation |
| 60 fps | 30 fps | 50% | Every frame is real at half speed |
| 120 fps | 30 fps | 25% | Phone "slo-mo" mode on many phones |
| 240 fps | 30 fps | 12.5% | Needs bright light; often lower resolution |
Filming for slow motion
- Use the phone's slo-mo mode (iPhone: Settings → Camera → Record Slo-mo to choose 120 or 240 fps, depending on the model) or a 60 fps setting.
- Use lots of light. High frame rates mean short exposures; indoor slow motion gets dark and noisy.
- Keep the camera steady and frame the action with room around it.
- Start recording early. The moment you want to slow down is easy to miss (more filming tips).
Slowing down normal footage
Most editors let you set a clip's speed (50%, 25%); DaVinci Resolve's Speed Warp is built for this. For 30 fps footage below 50%, turn on frame interpolation if your editor has it (DaVinci Resolve's Speed Warp, Premiere Pro's Optical Flow) to avoid stutter. It works best on simple motion and can smear fast, complex movement.
Speed ramps make it look intentional
A speed ramp eases from normal speed into slow motion and back; time it to the music for extra punch (cutting to the beat). It feels cinematic; a sudden jump to slow motion looks like a glitch. Ramp in over 0.2–0.5 seconds just before the key moment.
Our example: a youth soccer season
21 phone clips became a youth soccer season highlight, then one message added a crest, slow motion and a stadium anthem. Sped up. Phone-size version.
We asked: "Slow down the best moments: the strongest kick and the biggest celebration at half speed, with a quick speed ramp in and out." We didn't say which clips those were. Novacut found the kick (the boot meeting the ball) and the biggest celebration (an arms-raised jump) itself, set both to half speed with ramps, and named the clips it chose so we could check them.
FAQ
How do I make a video slow motion on iPhone?
Record in Slo-mo mode in the Camera app. Afterward, in Photos, tap Edit and drag the markers under the timeline to choose which part plays slowly.
Why does my slow motion look choppy?
The footage was filmed at a normal frame rate and slowed too much. Film at 60–240 fps, or use frame interpolation (Speed Warp, Optical Flow) when slowing 30 fps footage below half speed.
How much slow motion should a highlight video have?
One or two moments. If everything is slow, nothing feels special. Highlight video tips →
Should slow motion have sound?
Usually not the original audio, which sounds odd slowed down. Let the music carry it, or add a sound effect on the impact.
Sources: Apple, Photos for Mac: slow-motion playback options; Guiding Tech on iPhone slo-mo settings. Checked October 2026; frame-rate options vary by phone model.
Footage: Kampus Production on Pexels (Pexels License). The team name is fictional; the players shown don't endorse Novacut.