TL;DR: you can see it, with a slow-motion video.
Most Rolex calibres in the calibre overview run at 4 Hz, which means the seconds hand moves in 8 small steps per second. At 5 Hz it’s 10 steps per second. On a normal video both look like a sweep; in slow motion you can count the steps over one second. Rolex even matched the dial to it: the flange’s minute track is graduated to the half-second.