How the Special Effect of Slow Motion Works

Welcome to The Queue — your daily distraction of curated video content sourced from across the web. Today, we’re watching a video essay about how slow-motion effects work.

Slow-motion is one of those things I think I understand until I’m actually pressed to explain what it is. Which is exciting! One of the best feelings in the world is untangling something you took for granted and figuring out how it works. It’s like learning a new recipe or solving a puzzle. It makes the way you experience the world just a little clearer. And that’s neat!

So, the visual effect of slow-motion: how does it work? Well, from the name you can ascertain that it has to do with the way time feels on-screen. And when it comes to moving images, how time feels is largely beholden to frame rate, or the number of consecutive still images that appear on a display per second.

We associate cinematic “real-time” with twenty-four frames per second (fps). By stringing together twenty-four consecutive frames, we experience the illusion of motion, just like a flipbook. Now, if you were to shoot one second of film at 60fps and set it to playback at 24fps, that one second of real-time would now take 2.4 seconds to play out. The motion would appear slowed and unblurred because there are more frames to stitch the motion together. So: the more complex and fast the motion, the more frames will be necessary to sell the illusion that time is moving slower and to keep things from looking “jumpy.”

But all of this is much better seen than described. So, press on to today’s video essay which breaks down not only how the effect works, but how it transitioned, over one-hundred years of film history, from a technological hurdle to an established trope and aesthetic.

Watch “How slow motion works“: