When camera manufacturers start talking (or at least creatively leaking) about twenty-plus-stop cameras, it might not be too much to wonder whether the end is nigh for the very concept of exposure. That’s a pretty big claim, given it’s often been said that the first responsibility of a cinematographer is to expose properly, and if some inconvenient bit of technology is threatening to come along and assume that responsibility, it’s as well to know about it as early as possible so that everyone can take out unemployment insurance.
OK, that’s hyperbole, but compare what happened to sound. With 32-bit digital audio, the amount of headroom available is so stunningly vast that being a sound recordist on a major motion picture has practically become a work-from-home occupation (for the sake of truth in journalism, this is not true, but irritating soundies is a big part of what keeps the camera department entertained between setups, so we’ll proceed on that basis).
It’s easy to overlook just how enormous 32 bits of dynamic range is. For a long time, 16 bits was considered adequate, and 24 truly pro-grade. Just to make it very mathematically clear, 32 bits is not twice the dynamic range of 16. Every time we add a bit, we double the range of values (we can have all the values we had before with the new bit off, and all the values we had before with the new bit on). 16 bits can represent 65,536 values. 32 bits can represent… well, it’s up in the four point two billion range. 32 bits is 65,535 times the dynamic range of 16 bits, which is really a whole bunch of dynamic range.
Louder recordings
That’s enough to record Brian Blessed at his liveliest, and it’s made things like digital radio mics a lot more practical. For the sake of comparison, let’s say we have a competitive modern cinema camera – capable of fourteen stops, probably. That inevitably involves lots of clever mathematics around noise reduction and colour processing, but it’s very useful. The thing is, 21 stops is seven more than that. Seven stops is only as many stops as there are between f/2.0 and f/11, inclusive.
There are cameras out there which are diffraction limited above about f/4, but give or take a few NDs for indoors or outdoors, two to eleven is a bigger range of stops than most people actually use, on most productions. Let’s be clear, this is a thought experiment based on a press release claim. Still, a 21-stop camera creates a situation where proper exposure might, at best, require two positions – one marked “lots,” and another marked “less than that.”
Of course, that implies we’re willing to use up all of that dynamic range simply to avoid the inconvenience of glancing at a meter and twisting a ring on a lens. Invariably, we won’t do that, if only because there are quite a lot of reasons to set a stop on a lens other than making the picture brighter or darker. Assuming camera technology reaches the same sort of post-scarcity status audio has, we’re likely to use that flexibility to decide exactly how fuzzy we’d like our carefully-curated classic glass to look, or how deep we’d like the focus puller’s frown lines to become.
Bigger recordings
There are all kinds of practical problems with this, not least of which is how we might store such enormously capable material. We regularly shoot HDR material in ten-bit when it should really, mathematically, be represented in twelve. Clever things can be done with brightness encoding, although the PQ curve designed for current HDR was designed to do about as much as can be done. In theory, it handles brightness levels up to ten thousand nits, which is likely to remain fantastical for monitors but actually isn’t very bright compared to – say – the noonday sun. Whatever happens, we can add more bits, and more flash storage, and bigger editing workstations… and then, of course, someone has to come up with the piece of silicon that can actually capture that much light.
It’s easy to rest on the laurel that all these ideas are really quite a lot of R&D away from reality, although that’s a dangerous assumption in 2024. Claim warp drive is a long way off, and some chatbot on its night off will probably pop up with a pithy response containing comprehensive schematics. After all, there was a time when audio people might also have scoffed at the idea that level control might become a paperwork-only issue.