Zoetropes and the phi phenomenon

The brain works in weird and wonderful ways.

Earlier this week, we were treated to this image, from NASA, of the moon passing between the Earth and the DSCOVR satellite, 1 million miles in orbit:

DSCOVR Moon Transit

Just look at how beautiful that is.

Maybe it’s the wobbly way the Earth moves slightly downwards at the beginning of the shot, or the almost fake-looking crispness around the perfectly lit moon—the Sun, it turns out, is immediately behind the camera, so we’re actually seeing the rarely glimpsed far side of the moon—but something about this has that very hand-made, Harryhausen feel to it.

The DSCOVR animation also, in that way only the human brain can, sparked a connection with similar videos I’d seen only a few days before, on the blog of John Nack, ex Product Manager for Photoshop, now working on the Google Photos team:

The effect is basically a three-dimensional Zoetrope.

The Zoetrope—or “Wheel of life”—is a circular drum with a strip of photos lined up around its inside edge, invented over 150 years ago. A corresponding number of slots around the top of the drum let you peek in and—thanks to the phi phenomenon—see the still images come to life.


If you turn a Zoetrope inside out (so the images rotate on the outside of the drum) and then replace the images with 3D models, you get a towering stop-motion monster like the Pixar display above, which can be viewed from 360 degrees.

Problem is, you’ve now removed the slits, so you need some other way of chopping the scene up into “frames” or snapshots, to fool the viewers’ brain into thinking it’s a single object that’s moving in place, rather than a bunch of objects rotating around each other like teacups at a fairground.

If you’re just filming your Zoetrope, that’s easy – cameras already chop scenes into frames, you just have to get the frame rate right. But for live installations, Zoetrope builders cleverly use strobe lighting to act as a gigantic shutter for everyone’s eyes. It’s genius!

When you film in one of these strobe situations, and your camera framerate doesn’t match up with the strobe, you get to peek behind the curtain and see the strobe in action:

So there I am, watching the transit of the moon, and the transit of Buzz Lightyear and friends, when I realise, hold on, I’ve seen this done before, but slightly different again:

That’s the music video for Fear and Delight, by Soho electro-swing two-piece The Correspondents. Its director, Naren Wilks, put the band inside a room-sized Zoetrope, fitted with a dolly of rotating cameras, meaning the same single actor could be recorded from up to 16 angles simultaneously, then looped, creating this weird, all-directions-at-once kaleido-zoe-scope thing.

It’s beautiful. And it rightly won Wilks two gongs at the Berlin Music Video Awards 2014. If you’re interested in how it was made, check out this “making of” feature with the director:

So, three cheers for stop motion animation everyone! And an honorable mention to Zoetropes, old and new, for making the impossible possible.