First, HFR solves a couple of problems, especially for 3D. At 24 fps, when the camera pans or an object moves quickly across the screen, the image smears with "judder" or "strobing," which is annoying in 2D but infuriating in 3D. Higher frame rates reduce or banish strobing.
Higher frame rates also let projection get brighter. With brighter light comes more flicker. If the frame rate goes up, flicker goes down, so brightness can go up, too.
In fact, movies would flicker at even today's standard light levels, but each frame is flashed two or three times, depending on the projector, to prevent flicker. So in that sense, projectors have been delivering a sort of ersatz version of HFR (48 or 72 fps) all along.
But frame rates do change the look of the picture radically. While movies were at 24, standard-def TV was 30 frames per second. The difference between 24 and 30 may not sound like a lot, but it is.
During the High Frame Rates panel at the recent SMPTE Summit on Cinema, Northrop Grumman Aerospace's Stephen Long took to a microphone to discuss research his company had done on frame rates a decade ago.
"We learned very quickly that the 'film look' was all about 24 (fps), it's not about film," Long said. "As soon as we rotated the variable speed to 30 it looked like television. When we cranked it up above 50, it started to look different than anything."
Long's team found a "jump" at around 54-60 fps.
"Wow, something changed," he said. "It looked better. That's not a scientific description. It changed the perception, the sense of reality."
Doug Trumbull, who pioneered HFR movies with his Showscan process, followed Long to the mic and said his research had shown a similar jump at around 60-66 fps, leveling off at around 72. Trumbull also added that "Single-flashing is vitally important to keep continuity of motion."
Asked why "The Hobbit" is being made at 48 instead of 60, which seems to be "better," Phil Oatley, head of technology for Park Road Post, said "Because we can't show it (60) yet. ... It came down to how can we get a high frame rate film made by the end of the year?"
That's why I don't think 48 fps is going to be the new standard: It's an only an interim step.