The ‘Rolling Shutter Effect’ and the Mobius Action Camera

While using my Mobius camera to record some footage while skiing, I encountered a pretty unusual problem, at certain points the recorded video began to distort and the whole image looked as though it was ‘wobbling’. After a bit of research I discovered this was a pretty well known phenomenon known as the ‘rolling shutter effect’.

A pretty thorough explanation of the rolling shutter effect can be found on Wikipedia. Essentially the effect is caused by objects in the frame moving faster than the pixel values can be written to memory. The effect is maximised when the camera vibrates at a sufficiently high frequency.

The video above is a particularly bad (or good?) example of the rolling shutter effect, in subsequent videos I did a better job of mounting the camera and the effect was reduced. The implications for potential future uses of the Mobius and 808 #16 camera are interesting though, if I intend to use these camera in situations with large amounts of vibration (such as a Quadcopter….) I will need to look at isolating the camera from any vibration source.

It’s also interesting to note that this effect can be noticed in some very high end cameras, as they make use of the same digital sensor technology (CMOS) as the Mobius. More expensive cameras than the Mobius try to minimise the rolling shutter effect by using hardware that writes pixel colour values to memory as quickly as possible, thus requiring a higher frequency vibration for the effect to be observed. In practice however the reason these cameras often display less of a rolling shutter effect is because they are heavier, and by having more mass their frequency of vibration for a given input (exciter) vibration will is lower.