I spent half my live seeing the world through a video or film camera viewfinder, but I've never heard of the effect being seen directly by a human in sunlight.

Maybe in flickering streetlight, but not sunlight.

I read in an old astronomy book that a 18th Century scientist wondered if stars ever appeared to go completely "out" when they twinkled, and he figured out a way to see it. He observed them through a mirror and he saw them go out (dim to black) when he wiggled the mirror. Seems that with our "persistence of vision" we can't usually see this without a wiggling mirror.