4 ms·
Unfortunately this exhibits the usual confusion between pixel pitch and resolution, which makes it completely wrong. > Studies show that someone with 20/20 vis
by PaulAJ 6y ago
Unfortunately this exhibits the usual confusion between pixel pitch and resolution, which makes it completely wrong.
> Studies show that someone with 20/20 vision (or 6/6 in Europe) can distinguish something 1/60 of a degree apart. This means 60 pixels per degree [...]
NOOOOO!
"Resolution" is defined as the closest distance two dots can be while still appearing as two distinct dots. If you have two dots shown on adjacent pixels then you just see one big dot. You need the two dots separated by a pixel in order to see that there are two dots, so the resolution is half the pixel pitch. Worse yet, the two dots might be diagonal, so you need an extra factor of sqrt(2) in your resolution calculations. This means that the pixel pitch of a TV screen is 2 * 1.41 ~= 3 times its resolution. You need 180 pixels per degree if you have 20/20 vision, not 60.
And it gets worse. Everyone knows that 20/20 vision is "normal". Well, not quite. 20/20 vision is the average without correction. Once you include glasses, 75% of people can actually see better than that, and some quite a lot better. So to be safe lets bump the pixel density up by another third, to 240 pixels per degree. That gives 7,200 pixels on a 30 degree screen.
- dharmab 6y agoNot to mention subpixel rendering and antialiasing, which can make a perceivable difference, e.g. text vs. video games.
- elchief 6y agoso how big a tv should I get?
- nonninz 6y agoSo does this essentially mean that all those people who say things like "You don't need/can't distinguish 4K if your nose isn't touching the screen()" are wrong? I have always thought it was a strange thing to say. I can definitely see the difference between a 4K stream vs a 1080p one, even when the screen is much more far away than the recommended distance... () An hyperbole, obviously.
- timpattinson 6y agoTo be fair the difference in bitrate between 1080/4k is probably (in my opinion) a bigger difference than the pixel count, uncompressed 1080 looks pretty damn good. but yeah the "the eye can't see >20fps" or a certain dpi is definitely BS.