We hold accurate technical knowledge in pretty high regard around here, which is why this video from YouTube channel SmarterEveryDay was such a pleasant surprise.
In 7 minutes, engineer Dustin Sandlin does a fantastic job explaining rolling shutter with plenty of useful examples where he simulates the rolling shutter effect using high-speed camera footage and After Effects. In this way, he can actually show you how rolling shutter distortion happens; in fact, he can recreate it perfectly:
In the example above, he basically recreates what happens in every single frame of a 24fps iPhone video when you’re recording an airplane propeller. As the green line moves down, it scans the prop… but the prop is moving, and so it’s causing this strange distortion known as the ‘rolling shutter effect.’
In this example, he actually traces the lines as your camera is seeing them over the course of the exposure:
You will capture different patterns depending on which way the propeller is rotating, but it’s not a guessing game. You can actually visualize it when you slow the footage way down the way Dustin has.
But he doesn’t stop with propellers (which is where most breakdowns of rolling shutter end), he goes on to show you how this affects cell phone video of all kinds of things. Fidget spinners, a coin spinning on a table top, guitar and mandolin strings, you name it: the rolling shutter effect visualized and simulated/recreated by using high speed footage.
Definitely check out the full video up top to really see rolling shutter in action. If you’ve always had a hard time conceptualizing how the rolling shutter effect worked, and why it produced the shapes it does, you won’t find a better side-by-side comparison than this.
And if you like this, definitely check out Dustin’s YouTube channel. This is far from the only interesting, educational and just plain cool thing on SmarterEveryDay.