If you’re even remotely interested in literature, film, cinematography, Martin Freeman, or New Zealand, you probably know that The Hobbit trilogy, Peter Jackson’s adaptation of the J.R.R. Tolkien novel, has been filmed at 48 frames per second, and will be projected at that rate in many cinemas. The debate about whether this signals the death of cinema or the beginning of a new innovation in filmmaking will probably continue long after the release of the film, in the same way 3D is still criticised today. However, before hysteria grips the world and an angry mob with torches invades the Weta Workshop, it’s important to remember that the film is likely to be presented at the traditional 25 frames per second as well – in fact, not all cinemas are even equipped with projectors capable of playing the film at the higher frame rate, although most will receive a software update to allow them to play the new format.
Above is the trailer for the film at the standard frame rate. No footage at 48fps has been publicly distributed, partly because computer hardware would need to be faster to play back the footage at high resolutions, and partly because audiences might find it very jarring when only exposed to a short segment. There are a few reasons for this, so it’s time to get technical. Hold on to your lens caps!
- Frame rate:
Shooting at 48 frames per second simply means the cameras are taking 48 still images per second, which is double the cinematic standard of 24 frames per second. 24fps creates the famous ‘flickering’ quality of film, caused by the gaps between frames, which effectively render as black on the screen. Film running at 24fps is fast enough to only have that mild flickering quality while maintaining believable motion. When this frame rate is doubled to 48fps, those black intervals between frames are now twice as short, and much harder to notice. This means the flickering quality disappears in favour of smooth motion. The viewer now sees twice as many images, or twice as much information, each second.
- Shutter speed:
To capture enough detail while maintaining enough motion blur to make movement appear fluid and smooth, camera operators employ the 180° shutter rule. This refers to actual film cameras which have a semi-circular, or 180° shutter. As one frame of film is exposed, the shutter rotates around to block it as another frame is fed in, at which point the shutter has rotated far enough for the next frame to be exposed. Tyler Ginter has a very detailed post explaining the mechanics of it, with a helpful diagram (see below). When dealing with digital cameras, shutter speed can be set by the actual speed, ie. 1/48th of a second, which happens to be the correct 180° ratio for motion blur and detail when shooting at 24 frames per second – simply a process of doubling the number of the frame rate. When shooting at 48 frames per second, the shutter speed must therefore be 1/96th of a second. This has two consequences. Firstly, motion blur is now half as pronounced as it was, meaning more detail is actually captured in each frame, which assists in achieving more fluid, intelligible motion in action scenes or anything involving a lot of movement. Secondly, the faster the shutter speed, the less each frame is exposed to light, meaning the image will be marginally darker, and other parameters may need to be adjusted slightly to achieve the best exposure.
- Screen size:
This is a factor people consider less and less now that every film or TV show is available to view on screens which dramatically vary in size. In this case, 48fps is actually going to have the biggest impact on the big screen. The reason for this is simple – the larger the screen, the longer it takes for the viewer to process the entire image. This doesn’t help if it’s a fast paced action scene, cutting between shots every second. This was one of the challenges The Dark Knight faced when Christopher Nolan decided to shoot on the IMAX film format (see diagram below). Due to the sheer size of the film and screen, the editors had to reduce the pacing of cuts to prevent viewers becoming disorientated. In contrast to this, 48fps might actually be a way to unify a film’s look on different sized screens. It will look ridiculously smooth on any, if not jarringly so, but more importantly, with the greatly reduced flickering and motion blur, this high frame rate is actually easier to process and therefore reduces eye strain, as well as assisting in integrating CGI realistically. This also means greatly reduced eye strain during 3D projection, so it would not be surprising to see 48fps become popular simply as a means to make 3D comfortable to watch.
None of the improvements higher frame rates offer seem like something to complain about, but the reason they get such a polarising reception is understandable. Primarily, viewers often find the image so life-like that it appears fake, or like a ‘soap opera’ – it looks cheap, in short. Some believe this is caused by the uncanny valley phenomenon, in that when you make something fake look realistic, it unnerves people. However, 48fps isn’t that big a jump to suddenly make suspension of disbelief impossible. The reason so many people find it off-putting is more likely to be the fact that they are so used to 24fps; the standard for decades. Every movie we have ever watched has been at 24fps and even on TV, the NTSC format found in North America and Japan is barely 30fps.
To get an idea of what the film might look like, Luke Letellier decided to digitally alter the 24fps trailer using algorithms and witchcraft (Nuke, Kronos and After Effects) to create a 48fps trailer, which you can download in low or high resolution, or even medium quality if you have an ‘average’ computer. While the low resolution version will play back on older hardware, the effect is less pronounced at a small size. You can also see a similar effect on televisions with smooth motion modes, where they artificially double the frame rate, although this won’t look as good as a native high frame rate presentation, simply because adapting 24fps to a higher rate is an attempt to create information where there wasn’t any to begin with.
High frame rates are something audiences have never really been exposed to outside of the odd theme park ride, and we really won’t know whether they can actually get used to such a dramatic change while watching the film until it’s released. Whether astounding or unwatchable, it will certainly take us somewhere unexpected.