At high speeds, the movement of objects and substances like water look like blurs to the naked eye. But as Joey Schenkenberg (a.k.a., Joey Shanks) proves on his Shanks FX YouTube channel for PBS Digital Studios, with a fast enough shutter speed, a camera can make objects seem as if they are frozen in time. The effect, as Shanks explains, is known as “temporal aliasing,” which can be observed in slow-motion propellers, spinning rings and other objects.
Shanks uses this temporal aliasing to trippy effects when he combines it with a 24 Hz bass tone sent through a speaker. This makes the water vibrate 24 times a second in circular motion, mimicking the standard film speed of 24 frames per second. With a fast enough shutter speed (to create super-slow motion), the camera effectively captures the same image frame after frame, as Shanks explains, making the water seem to defy the laws of physics by bending and curving in midair. A 23 Hz tone creates a reverse flow effect.
“I was first inspired by a video I saw by BrussPup, a really cool YouTube creator who does a lot of optical illusions, and he did pretty much the same thing I did—it was just amazing [to see] the helix patterns he could make by using the same technique,” Shanks tells The Creators Project. “He listed the ingredients and materials, but he didn’t go really in depth into how to actually achieve this because whenever I showed this video people thought it was fake.”
To get around this, Shanks placed objects in the frame to prove that the footage was shot in real-time, including himself, trees blowing in the wind, or something spinning in the background. The trick to making this all work, he says, is to make sure the speaker’s output makes contact with the water.
“It was a pretty fun thing to do, though I probably should have waited to do this until April or May because it was freezing out,” Shanks says.
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