A long time ago, movies were distributed to theaters on photographic film. What medium is used in modern times?
Lot of theaters are starting to use digital projectors now. I believe the romantic comedy Bounce, starring Ben Afleck and Gwyneth Paltrow, was the first movie to be formatted for digital projectors.....don't ask me why i know that. I don't know how IMAX works but regular theaters still use thise movies reels, usually 2 per movie where an image is project frame by frame. I maybe wrong though.
Digital video technology has not yet caught up with photography. The resolution of a digital image is not as good as 70mm film. The only theaters that can use video are those crappy multiplexes in shopping malls, where you're looking at a screen about twice as big as your rich neighbor's home rig. Real theaters with real screens still use film.