Just a random question only for the sake of curiosity ....
Sometimes you will see a live telecast - football say - where part-way through a shot the cameraman changes aperture - when the ball enters the shade of a grandstand, for example. But you don't see this too often, presumably cameraman and director conspire to make changes while the particular camera is not live to air.
But what about the movies? Let's say you have a shot that starts with the distant horizon (very bright day) and pans around to some figures in the middle distance who are in shade, then zooms in to start the conversation between them. (All in one shot.) You often see this general sort of thing. Obviously, the correct exposure is different at the start of the shot and at the end of it. If you shot that with an ordinary camera, you'd have obvious "steps" where the cameraman stopped down from (say) f/11 to f/10 and these would be quite visible. Given that I've never noticed this, I suppose that serious movie cameras have the ability to stop down steplessly and smoothly over any desired number of frames.
Does some kind soul know for sure?