Slow-motion video can accomplish different things for a filmmaker. Slo-mo is often used to dramatize emotion and set a mood, but it’s also used in action films and nature videos. For example, there’s a huge visual impact in slow-motion of an explosion’s pyrotechnics or the wingbeat of a hummingbird.
Shooting high-quality slow-motion used to be impossible without expensive cinema cameras, but the democratization of content creation has only been possible because cameras have gotten cheaper and faster. And with the advent of the iPhone and its 240 fps (frames per second), even super slo-mo is possible.
What is slow-motion?
Video is nothing more than multiple still images or frames stitched together in quick succession, creating the illusion of motion. This is why frame rates matter. The frame rate is the rate at which the camera records images. Most video is displayed at 24 to 30 frames per second. You can think of a video sequence like a flipbook. If you flip 24 to 30 pages of a book in one second, the images appear to be in motion.
If you want that motion to appear slower, you need more images to make up the 24p timeline. For example, if you record 60 frames per second, you can slow it down by half; 120 frames can be retimed to 25%, and so on. The more frames per second you can record, the more detailed and sharp your slow-motion will appear. You can slow 960 fps down to 3%, creating super slow motion.
Can you slow down footage that wasn’t shot in a frame rate higher than 30 fps? Technically, yes, you can, but it won’t look good. It will look choppy and stuttered. That’s why you need to pay attention to frame rate when shooting. It’s not usually a problem you can fix in post!
How to shoot slow-motion on your camera
Shooting in slow motion can elevate the visual appeal of your videos, adding dramatic flair and highlighting details that might otherwise go unnoticed.
Here are the steps to help you capture compelling slow-motion footage:
Choose the Right Equipment: Start with a camera that can shoot at high frame rates. You’ll also need good lighting and a stable tripod to prevent shaky footage.
Frame Rate Settings: For standard slow motion, aim for 60fps, but for more dramatic effects, you can go up to 1,000fps.
Shutter Speed: For the best results, your shutter speed should double your frame rate. If you’re shooting at 60fps, set your shutter speed to 1/120; for 120fps, set it to 1/240. This helps prevent motion blur and ensures smoother slow-motion playback.
Plan Your Shot: Slow-motion footage can dramatize movement and detail, so plan your shot to make the most of this effect. Consider how the slow motion will enhance your visual story, whether it’s a dynamic action scene or a detailed close-up.
Pro tip:
Creating slow-motion footage is more than just a technical process; it’s an opportunity to add depth and emotion to your videos. Take the time to experiment with different frame rates and subjects to see what works best for the story you want to tell.
How to shoot slow-motion on your phone
- Locate the frame rate settings. Select a frame rate of 60 fps or higher. Some phones simply indicate the option as “slo-mo” or “slow motion.” Keep in mind that slo-mo clips are bigger in file size, so it’s better to limit them to 10 or so seconds in length.
- Keep the camera steady. You don’t want to cause the camera to lose focus or blur your image through motion. Plan your shot beforehand, framing your subject precisely, then tap the focus square to lock focus. Practice shooting people or objects you can direct and control, such as hair blowing in the wind or water pouring out of a pitcher into a glass. Then, move on to shooting more dynamic subjects like athletes and animals.
The best cameras for slow-motion
Whether you’re just starting out, looking to upgrade, or need professional-grade equipment — here are some great slow-motion cameras:
Beginner
Intermediate
Professional
How to edit slo-mo footage
You don’t need pro editing software anymore to handle slo-mo video, though you may want to consider that file sizes will be heftier, and pro software gives you the option to create lightweight proxy files and is all-around more robust. For a few phone clips, take advantage of built-in Android and Apple apps. For pro work or long-form, you’ll want to use editing software like Adobe Premiere, Final Cut Pro X, DaVinci Resolve, or Adobe After Effects, to name a few.
When slowing down footage in your timeline, you’ll need to do a bit of math.
Here’s a cheat sheet that spells out frame rates and their respective lengths:
| Frame rate | Length |
|---|---|
| 30 fps | 1 second |
| 60 fps | 2 seconds |
| 120 fps | 4 seconds |
| 240 fps | 8 seconds |
| 480 fps | 16 seconds |
| 960 fps | 32 seconds |
If your timeline is 24p, you’ll need to evenly divide your recorded frame rate by 24 to determine the speed at which your footage can be reduced. Same thing if your timeline is 30p. Try to evenly divide to get the correct retiming percentage, or you may have half-frames that cause the footage to look choppy.
The one little bit of fixing you can do in post is time interpolation. It’s a setting that allows you to change the clip’s frame rate by leveraging optical flow to interpolate missing frames. That may sound quite complicated, but experiment with it, and you’ll see. The alternative to the optical flow setting is frame blending, which merges two neighboring frames to reduce stutter, essentially stretching out the footage. Stick to frame blending for clips that are at 50% speed or higher.
If you’ve shot slo-mo so you can employ speed ramps, here’s a pro tip: apply motion blur. Motion blur plugins for FCPX work well to add a touch of blur to smooth out transitions. So, if you’re shooting a surfer cresting a wave and want to ramp down the speed just as he catches air, apply motion blur in that transition from 100% speed to 50% or less. It’s an easy way to add a pro touch and elevate the quality of your footage.
Conclusion
Take advantage of the dramatic effects and visual impact of shooting slo-mo, pay attention to frame rate both while you shoot and edit, and don’t forget to include stock footage from Artlist’s extensive library. You’ll find various slo-mo and super slo-mo video clips, from misty waterfalls to science studio experiments.
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