## The Math Behind the Rolling Shutter Phenomenon

I remember seeing the photo above on Flickr once, and having my brain melt slightly from trying to figure out what went wrong.

The issue was the propeller was rotating as the camera detector ‘read out’, i.e. there was some motion during the exposure of the camera. This is an interesting thing to think about, lets have a look.

## Using a Camera’s Rolling Shutter Effect to Create a Display

I’ve got a few days before my big summer vacation, so I thought I’d hammer out an incredibly impractical display technology!

## What a DSLR’s Rolling Shutter Does to a Speaker Playing a 61Hz Tone

Here’s another example of a strange effect caused by the shutter of a DSLR. YouTube user drummaboy5189 captured the above video by playing a 61Hz sound through his speaker and then pointing his Canon 6D at it while filming at 60 frames per second and 1/4000s shutter speed. What resulted is a “rolling speaker” effect.

## Finish Line Cameras and Slit Scan Photography

Yesterday we reported on how US Track and Field saw its first “photo finish” tie this past weekend in an Olympic qualifying race. If you thought the finish line photo looked strange, it’s not just you: it’s not an ordinary photo. Journalist Daniel Rutter has written up a great article on how finish line cameras work:

[…] most finish-line cameras aren’t super-high-speed movie cameras, but instead a kind of slit camera. A slit camera has a line-shaped lens, which exposes the film or electronic sensor line by line or column by column, not unlike the way a rolling shutter works. The critical difference, though, is that a slit camera can keep on going past the lens indefinitely. You can keep collecting image data, or keep spooling film past the slit, for as long as you have memory or film. The shutter never closes as long as the film or memory lasts, so it’s impossible to miss any action between the frames.

[…] imagine taking a flatbed scanner sensor and setting it up vertically, looking across a racetrack at the finish line. Start a “scan”, and it’ll authoritatively tell you when every body-part of every runner makes it to the finish, by simply showing that part of that person before any part of anyone else. The speed of the scan should be set to roughly match the speed of the runners, so they look generally the right shape, but any part of any runner that stays stationary relative to the scan rate – a foot on the ground, for instance – will seem long. Any part that’s moving forward relative to the scan rate – a hand or foot coming forward, for instance – will seem short. Even if you mess up the scan rate so everyone looks wide or narrow, whatever part of whatever runner shows up first in the scan is the first to cross the finish line.

Elastic athletes [How to Spot a Psychopath]

Image credit: Slitcam-Math by VanDerMouche

## Crazy Rolling Shutter World Captured by Camera Attached to Helicopter Rotor

You’ve probably seen videos showing the rolling shutter effect turning airplane propellers into boomerangs, but what if the camera was attached to the spinning object rather than pointed at it? mguw of Helidigital decided to find out by attaching a small camera to the rotorhead of an RC helicopter, synchronizing the RPM of the rotor to the scan rate of the camera. The result is an uber-trippy video in which reality is bended through the rolling shutter effect.

## Wacky Rolling Shutter Effect Captured by iPhone Placed in Guitar

Kyle Jones wanted to see what it was like to film from inside a guitar, so he stuck his iPhone inside and started recording. The resulting footage shows the strings vibrating in wacky wave patterns thanks to the rolling shutter effect, which we also saw in the Canon 5D Mark II footage of a bass player shared earlier this year.

(via Reddit)

## Strange Effect When Shooting Bass Player with a Canon 5D Mark II

urbanscreen discovered this strange string-wobble effect when shooting a bass player with a Canon 5D Mark II. No special effects or slow motion were added to the footage — what you see results from the frequency of the strings and the fast shutter speed of the camera. Here’s another video showing the same effect from different angles.

Can anyone explain what’s going on here?

## Rolling Shutter Causes Plane to Drop Boomerang Bombs

The rolling shutter used by the majority of consumer CMOS sensors can do crazy things to photos and videos. The video above shows what an airplane propeller looks like when shot with a Nokia N95. The rolling shutter makes the plane looks as if it’s dropping boomerang bombs that quickly disappear into thin air.

This topic also came up a couple weeks ago when a strange photograph of a boy caused debate regarding whether or not a rolling shutter was the culprit. In case your wondering, DSLRs have this issue as well.