As a major tolkein fan [read: nerd], I wanted to write a post honoring the release of The Hobbit: An Unexpected Journey. Living with two filmmakers, I’ve been privy to a lot of criticism surrounding The Hobbit’s *48 frames per second* frame rate.
Frame rate refers to how many frames, or consecutive images, are shown in a given second, while shutter speed relates to the length of time each frame is exposed for. The higher the shutter speed, the shorter the exposure time, or the length of time the camera is open. since the 1920s, movies have been shot at 24 fps and at a shutter speed of 48 [1/48-second exposure time]. This convention is responsible for the motion blur and choppy cadence that has become a part of the cinematic language we have grown up with. Nonetheless, with the advent of new digital film-making technologies, directors like James Cameron and Peter Jackson have begun pushing for the use of high frame rates (HFR) to enhance the movie watching experience. Double your frame rate, double your fun.
Our brains actually only need a frame rate as low as 14 fps to piece the images together enough to perceive constant imagery. Of course, the more frames we have, the smoother the motion, which goes back to the impetus behind using higher frame rates in film. The Hobbit, however, which was shot at 48 fps with a shutter speed of 60 [1/60-second exposure time] has been criticized for this smoothness, which is curious considering hollywood is a place where more is typically… more. Critics have said it just looks too real—that this hyper-reality takes the viewer outside of the movie-watching experience.
The retinal cells of the human eye respond to light [the rods] and color [the cones], releasing chemical messages to the optic nerve. These messages are translated into nerve impulses that then travel up to the brain, where they are pieced together and interpreted as images. Because the world is theoretically in constant motion, our eyes are well-accustomed to handling an infinite frame rate, which is not to say that they record everything they encounter. Because our retinal cells cannot send out signals at an infinite rate, the retina only records a subset of those infinite frames. Though I could not find a consensus, our eyes see somewhere between 100 and 500 fps.* Even then, only a subset of that subset of frames actually gets interpreted by the brain. You can think of the whole process as a sort of information overload for the brain, which only needs a small chunk of that information to actually make sense of it.
Because our visual processing systems can only handle a sub-infinite frame rate, the world our eyes perceive has a natural degree of blurriness. With this in mind, not having seen The Hobbit yet, I would already agree that the frame rate is likely problematic, but not because it makes the movie look ‘too real’. 48 fps is still well below the 100-500 fps frame rate at which we see the real world. However, the crucial difference is that, for technical reasons, they shot the film at a higher shutter speed, reducing the exposure time for each frame. Because the camera is capturing an image for a shorter length of time, it records less blur, making for a much crisper picture [see here for a great example of these effects]. Consequently, The Hobbit-watcher’s eye is experiencing less frames per second at a much higher clarity than in real life, giving our brains more time to take in all the details that we ordinarily cannot see.
This clarity and astonishing detail make for a viewing experience that is nothing at all like our reality. The Hobbit is thus using a completely novel visual language than the one we are accustomed to both in reality and in film, making for a different kind of unreality. Of course, HFR technology is still in its infancy. As more pro-HFR filmmakers continue to experiment, a more palatable and less dizzying aesthetic that is better adapted to our visual processing systems can hopefully be reached.
Meanwhile, hope remains while fans are true…
* When it comes to neuroscience // neurophysiology, we have a literal blind spot because we are using our brains to understand something about our brains. From my reading [and this is by no means my field of specialty] there seems to actually be very little consensus about what is going on with our visual perception, at least with how it relates to the content covered in this post.