Created: 2019.10.18 | Last updated: 2020.06.25
Simple physics, and the fact that the human eye can 'rove' where a camera can't in a specific picture. Oh ... and God made it better than man has made cameras, at least so far. And when someday the camera does better, remember it was God that gave humans the ability to make cameras, so he still wins on the top quality rank.
If you read any of my blogs, you will know I make fun of Trumps claims that 'people keep asking me ...' when it is clear that the number in question is somewhere between 1 and -1. Note that the only number that could refer to individual people between 1 and -1 is 0. Also noting, for fun, that with 0 in English we use the plural form of 'people' but we use 'person' if there was one. So if one person ever actually asked him, he'd have to say "a person asked" but because no one did, he can truthfully say "people always ask me..." As in "Zero people always ask me..." See ... by using 'people' he is telling the truth, and I'll bet YOU thought he was lying.
I'd love to say "many people have asked me this question". But no one has in over 20 years. I still think it is interesting.
According to some sources like Wikipedia, the human eye has the ability to close it's iris down to about f8.3 in a very brightly lit place and open it up to about f2.1 in the dark.
On the 'big' number, if you didn't know, the bigger the number - the more things will appear in focus far away and close, and the smaller the number, the more you can see in the dark.
But anyone who has done photography for long knows that when you look at a scene, your eye with it's measly f8.3 sees much more in focus than a camera lens at f22. So what is happening?
The camera can only focus at ONE point (plane technically) at a time, but your eye, roving over the landscape can focus back and forth on different things much faster than any auto-focus I've seen on any camera.
OK, so what about in the dark, anyone knows that a human can see in the dark much better than any camera, even the Pixel 4 that in ads says it can 'see in the dark' and 'take pictures in the dark'.
The answer is simple: God made your eye much better than scientists have so far been able to make camera sensors. It really is that simple - your eye circa 2019 is still WAY better than any camera sensor. So ... you can see in the dark better than the camera can even though a camera can have a 1.2 or 1 or even slightly negative f stop - but you are stuck going only down to f2.1.
Another couple related factors: Your eye has color sensors and b&w I'll call them, sensors. The b&w are better in the dark - but they don't record color. And interesting side note, males have on average twice as many b&w sensors as females, that is the reason that ON AVERAGE males can see in the dark better than females.
Will cameras ever be better than the human eye? Sure, I suspect so. The human eye isn't the best that God created either, but I expect that eventually cameras will be better than those other creatures too.
Oh ... and if it is truly dark, you can't see anything, but to be fair an IR camera can, as long as you don't consider IR light as 'light' of course.
Funny one: If you have a Raspberry Pi and you want a camera that can see IR (Infrared) you need to get their 'NO IR' camera. Why? Because it is very poorly named. It means "NO IR FILTER" meaning it lets IR light through to the camera. So the camera that can see IR light is the 'NO IR' camera, and the camera that can NOT see IR light is the camera that does not say 'NO IR'. Really!