What is the actual physical process happening here?
In: 0
This “effect” only happens on recorded video, not when observing with your own eyes.
This is because video cameras have frame rates (typically 24, 30 or 60 fps), meaning they’re capturing an image every 1/24, 1/30 or 1/60th of a second.
Say a camera is shooting at 30 fps, there are a few things that can happen:
1) If an object is rotating at the exact same speed as the framerate (i.e. it makes one complete rotation every 1/30s) the rotating object [will appear stationary](https://www.youtube.com/watch?v=yr3ngmRuGUc).
2) If the object is rotating slightly faster than the framerate (i.e. slightly more than one complete rotation every 1/30s), it will appear to be moving in slow motion. Because every time the camera captures an image, the object will appear to be rotating just slightly clockwise, but in realty has rotated a full 360-degrees clockwise *and a bit*.
3) Similar to #2, if the object is rotating slower than the framerate (just under one revolution per 1/30s), it will appear to be rotating backwards because at each frame capture, the object will have almost *but not quite* completed a 360-degree rotation. Thus it will appear to be slowly rotating counterclockwise, relative to its position in the previous frame.
Latest Answers