The bulb on an old-style film projector flashes some 24 times a second; a typical CRT television screen changes frame 50 or 60 times every second. The fastest cameras in the world can snap frames lasting just a trillionth of a second short.
The technological significance of ultrashort flashes of light lasting below a quadrillionth of a second is rapidly increasing. In laser sources, groups and pairs of light flashes can be developed instead of separate flashes.