When Texan Al Brooks checked security camera footage from outside his home, he was in for a surprise. A bird appears to be floating as it flies by the camera, pausing for a minute to take in the environment.
This isn’t the product of a video effects artist; instead, it’s a stroboscopic effect. The bird’s wings were beating at the same pace as the camera’s frame rate, giving the impression that the wings were stationary. It’s the same effect you’ll see in a film where a helicopter’s propellers or a car’s wheels appear to be stuck, even if they’re moving.
When a camera’s frame rate exactly syncs up with flapping bird wings, this is what happens:
h/t: [Neatorama]