4K is about 25MP. That's around the resolution limit of 35mm film in still photography. The exposed area is considerably smaller in movies as the film is run vertically rather than horizontally.
Without getting into the old and terribly complicated film vs digital argument, I think it's widely agreed that 35mm and 4k are at least in the same ballpark of resolution, and that IMAX exceeds 4k, so I maintain that shooting 4k does not present any new issues around closeups or quick cuts.
