Here’s an interesting look at what the aperture blades on a Canon 18-55mm (the kit lens for many DSLRs) look like. The video above shows the blades moving into position at 120fps. This happens every time you shoot a photograph and in the blink of an eye.
Here’s the same lens at a smaller aperture setting (higher f-stop) recorded at an even slower 240fps:
(via Camera Technica)