There are two examples here. It might take you a second or two to see it well, but notice how the light pulses in the original. In the second example, (wider view) it’s very obvious what happens on the top left part of the test pattern chart. This is not a camera issue, but is another example of how a high-speed camera can actually “see” flicker in an electric light that is too fast for our naked eye to see.
Footage provided by Tom Heigi – DIT Phantom Tech