This video is in 3D.
Really, it is.
If you get a pair of sunglasses and you just cover your right eye,
you should see a 3D effect.
I mean, assuming both your eyes work, obviously, sorry if they don't.
The effect will work best on a big, bright screen,
in a bright room, wearing dark sunglasses,
and if your device is playing this at a high frame rate.
If you're just kinda lying in bed squinting and holding your phone out, it probably won't work.
Also, you look ridiculous.
Normal 3D video works by sending a different picture to each eye:
those two simultaneous images, one for the left eye, one for the right,
are called a stereo pair,
and they simulate what you would see with two eyes.
So you display two images on the same screen at the same time,
and then you use filters to show only one to each eye.
And that might be using a red and blue image and coloured filters,
or weird tech-glasses where each lens goes opaque 60 times a second,
or in a modern cinema, glasses that filter using polarised light.
But because there have to be two separate images on the same screen at the same time,
for anyone not wearing those glasses, it's a confusing mess.
But this video here works as a normal 2D video as well, at the same time,
and the reason is something called the Pulfrich effect,
named after Carl Pulfrich, the German optometrist who first documented it in the early 20th century.
Your eyes and brain take a little bit longer to process dark images than light ones.
Now, exactly how long depends on the relative brightness of the images,
but it's usually roughly around the length of one frame of video,
which is pretty useful for something first noted nearly a century ago.
If you put dark sunglasses over your right eye, then the image from that eye
will get delayed by about one frame on its way through your brain.
So you end up seeing two different images, one frame apart in time.
But that's not enough to create a stereo pair on its own.
The other ingredient is the bizarre, nausea-inducing moving camera.
Because that camera has constantly been in motion,
your right eye has been lagging behind by about one frame,
just as if there was a second camera just to the right of that one,
giving a separate stereo image to your right eye.
Now that's a stereo pair.
So if we stop the camera rotating, the effect disappears,
and everyone can take a breath.
That also works by moving the objects in the frame.
That's why, earlier, the cutaways I used had constantly moving backgrounds.
And sure, it's not perfect 3D.
But your brain fills in the gaps.
The Pulfrich Effect works well enough that it's been used for TV shows occasionally,
and for a couple of video games.
In the 90s, the BBC had a special series of 3D shows for a charity telethon,
including one of the worst Doctor Who productions ever made.
- "Who's that terrible woman?!"
But if you look at it, in every shot,
something in the foreground moves left to right,
and something in the background moves right to left.
Constantly.
So because every camera shot has to be carefully planned, and in constant motion,
you won't see Pulfrich effect videos in the cinema any time soon.
It isn't practical for anything more than quick, short gimmicks.
Gimmicks like this video.
You can take the sunglasses off now.
One take! One take!
Wait, did I go the right way there?