To be clear, STARVIS is a new sensor whose technology is mostly meant for applications in scientific, industrial, and security spaces. And Sony won't give out any "normal" number with respect to ISO yet, either. Part of that might be because actual ISO is difficult to determine, since the back-lit CMOS sensor places its photodiodes in front of other hardware components that, conventionally, would block a substantial portion of light information. But as unclear as the exact results are, here, the latest advancements in ultra-sensitive sensor trickery point to a new level of attainability.
Cameras continuously become more and more capable in low light. Every year, manufacturers release better APS-C sensors, larger, specialized sensors, filterless sensors, and even sensors that employ different methods of arranging pixels and combining the data we get from them. But something bigger seems to be going on, something aside from the one-stop every two years or so pattern that has stayed true for the last decade, more or less.
We're all familiar with Moore's Law (not Murphy's Law, simplified — Moore's Law states that the number of transistors we can fit on a circuit board doubles every two years, which sort of has the same effect, depending on how you look at it, on all technological advances). But at some point, physics catches up with Mr. Moore, requiring a bigger paradigm shift behind a technology to get it moving to new heights. On one hand, manufacturer's haven't necessarily hit any hard limits with low-light performance (look at the Sony a7S II, which continues to blow our minds). But on the other, it feels like we're about to jump a few stops more this year. Or perhaps we already have.
The recently headline-making Canon ME20F-SH shoots at ISO 4 Million, which is three stops above what Sony's ISO 409,600 a7S II can muster. Then again, the ME20F-SH is also six times the price. But these jumps are more important than they may seem for us as photographers and the future of low-light photography.
Some might blow these numbers off as ludicrous: "No one really needs that much sensitivity." But at the end of the day — aside from capturing sharper images with less noise at more reasonable light levels of general human activity — it's photography's ability to show us an otherwise unseen, completely new world (where's Scott Weinger?) that makes it so powerful. Canon's own slow-but-neat video promoting the ME20F-SH is a testament to that.
There is a very real problem, however, that starts to occur when shooting in extremely low-light scenarios, and you can start to see it in the Sony STARVIS footage: color isn't exactly accurate as it would be in daylight. As sensors become capable of differentiating between just a few photons, contrast and tonality become serious issues.
If zero photons hit a pixel, that pixel is black — no problem. But in an extreme example, let's say your sensor can measure the difference between individual photons. And let's say that over the time of a particular exposure, a maximum of three photons hit your sensor at its brightest points. If you're adjusting for your whites and blacks "correctly," that means that three photons hitting a pixel would convert to white (I'm being incredibly simplistic here on purpose). And that would mean that there would only be four possible shades (including black) of a given pixel. And the difference between each shade would be quite stark.
Sure, varying wavelengths would subsequently vary the actual color registered by each pixel, but that lack of variation would translate directly to an incredible lack of tonality and seemingly high contrast (potentially). So how would cameras handle this? Would there be ways to artificially increase the gradation between one shade and the next?
That's all for someone else to figure out. But the future holds a lot of interesting possibilities, the very least of which is slightly better noise performance at reasonable ISOs, even if that's what everyone cares about today.
Oh, and it's probably too late, but for those that haven't yet watched the video, let me save your brain by suggesting that you turn your sound off, first. Those that I didn't get to in time, I'm sorry that you'll now be falling asleep to the sound of "STARVIS" awkwardly playing in your head.