4 ms·

Resolution limit of the eye – how many pixels can we see?

65 points by bookofjoe 1y ago

fainpul 1y ago
This is helpful for estimating how much higher display resolutions are still perceivable and when we enter the territory of "marketing bullshit". For example: - 40 cm view distance (e.g. smartphone): 300 ppi is roughly the maximum that's useful - 100 cm (e.g. desktop monitor): about 200 ppi https://www.nature.com/articles/s41467-025-64679-2/figures/2 https://www.nature.com/articles/s41467-025-64679-2/figures/2
- cubefox 1y ago
  About 15 cm view distance for smartphones is pretty normal for me (shortsighted with glasses) on websites where the text is very small, e.g. Hacker News.
  - samat 1y ago
    I’ve started using text scaling on HN (Cmd++ on Mac, available on mobile, too) and it’s much easier to read and pleasant to the eye this way.
    - cubefox 1y ago
      Oh, that's a great idea. I see Firefox also has this in the settings under Accessibility. I guess I never looked there because I don't think of myself as disabled. (Maybe I should.)
      - bombcar 1y ago
        More and more - especially on Apple products - Accessibility is the "customization" menu, not the "disabled support" it used to be. Size increases, animation decreases (when your iPhone is getting old, turn off animation and behold it operating super fast!), etc can all be found there. I zoom websites until they "feel right" which is usually something close to "they are as wide as the window I have them in" - HN is a few taps up from "actual size".
      - trenchpilgrim 1y ago
        given enough time we all become disabled
- trenchpilgrim 1y ago
  I use my phone way closer than 40cm all the time...
  - dev_hugepages 1y ago
    You may have untreated myopia, or need to use a bigger font size (HN is guilty of this!)
    - trenchpilgrim 1y ago
      No I just sometimes use my phone while lying down lol
- noosphr 1y ago
  I remember those numbers being a third that 20 years ago. Either we have evolved brand new eyes without noticing or you are just talking about the current state of the art like it's the limit of human vision. Put another way look at 300ppi prints and 1200ppi prints. The difference is night and day at 30 cm viewing.
  - ncruces 1y ago
    ppi pixels ≠ dpi dots You don't need 1200ppi for a nice 1200dpi print; even 300ppi may be enough.
    - adrian_b 1y ago
      For printing photos, you are right that a 300 ppi printer is better than an 1200 dpi printer. On the other hand, for printing text, an 1200 dpi printer has the quality of an 1200 ppi printer. Many well-designed traditional typefaces have relied on optical effects caused by details that require for being printed a resolution higher than that at which the human eye can distinguish a set of bars from an uniform background (which is the object of TFA). For instance, in some typefaces the edges of the strokes are concave or convex, not straight, which could be rendered in a computer display only by either a much higher resolution or by more sophisticated pixel preprocessing methods (in order to simulate the effect on the eye). Whenever such typefaces are displayed at a lower resolution, i.e. on computer monitors, they are very noticeably uglier than when printed on paper by traditional metal printing methods or even by a high-resolution laser printer.
      - cubefox 1y ago
        A 1200 ppi display can use anti-aliasing, e.g. grey scale edges on text, while a 1200 dpi printer can't, I'm pretty sure. So the former has better quality.
- jl6 1y ago
  Higher ppi on mobile is still useful if it enables “manual zoom” (i.e. move your head closer). I do this with Google Sheets on mobile all the time, as I like to have a lot of the sheet displayed at once to see the overall structure, and then peer closer to read the text.
- adrian_b 1y ago
  You want to say "the minimum that is useful", because you want a resolution at least equal with that, to not see the pixel structure. A 27" monitor has a height around 17", i.e. about 43 cm, and for watching a movie or anything else where you look at the screen as a whole the recommended viewing distance is twice the screen height, i.e. about 86 cm. At this distance, the resolution needed to match the human vision is provided by a height of slightly less than 3000 pixels by this study, but by about 3300 pixels by older studies. In these conditions you are right, the minimum acceptable resolution is around 200 ppi. This means that a 27 inch 5k monitor, with a resolution of 2880 by 5120 pixels, when viewed from a distance twice its height, i.e. about 86 cm (34 inch), provides a resolution close, but slightly less than that of typical human vision. (That viewing distance that is double the height corresponds to the viewing angle of camera lenses with normal focal length, which has been based on studies about the maximum viewing angles where humans are able to perceive a correct perspective when looking at an image as a whole.) However, when not watching movies, but working with text documents, you normally stay closer to the monitor than that, so even a 5k monitor is not good enough (but an 8k monitor may be enough, so that might be the final monitor resolution, beyond which an increase is useless).
edelbitter 1y ago
One would expect the results to be highly correlated to corrected vision which is all over the place.. but they get suspiciously tightly grouped results. Did they maybe not measure how many pixels we can see.. but rather how laughably bad COTS IPS are at contrast, as the examined pattern approaches their resolution? I wonder what happens if you repeat that with a reasonably bright 16K OLED.
jdubb 1y ago
There's this classic by VSauce about the same topic: https://www.youtube.com/watch?v=4I5Q3UXkGd0 https://www.youtube.com/watch?v=4I5Q3UXkGd0
- Terr_ 1y ago
  I hate the fact that my very first reaction is: "That just got bulldozed."
drnick1 1y ago
Some people still say that 1080p is plenty, whether for reading text or watching videos (including gaming), but anyone who has used a 4K monitor knows that text looks far clearer and games look far more realistic and detailed at 4K. And the same will probably be true when 4K becomes truly mainstream on desktops.
- fnands 1y ago
  Yeah, I think diminishing returns kick in at some point. Going from 1080p to 1440p feels like a huge improvement. Going from 1440p to 4k (aka 2160p) is a little bit sharper. I don't think the jump from 4k to 8k will improve things that much.
  - bombcar 1y ago
    I can tell the difference between 1080p (or upscaled 1080p) and 4k on a 50" screen at "living room" distances, but it's nowhere near as obvious as SD to DVD was. At "laptop" screen distances the difference between my Retina display and non-retina external monitors is quite noticeable; so much so that I run 4k in 1080p mode more and more. 8k is going to require those curved monitors because you'll have to be that close to it to get the advantage.
    - ant6n 1y ago
      DVDs are SD, with 480 pixels of resolution for ntsc.
      - bombcar 1y ago
        Yeah I meant VHS → DVD (which was noticeable), and also SD → HD (1080p) which was again noticeable.
    - close04 1y ago
      > I can tell the difference between 1080p (or upscaled 1080p) and 4k Are you talking about the resolution of the video or of the screen itself? Lower resolution video looks worse also because of the compression. I saw bigger difference from video compression than from screen resolution. E.g. good 1080p video looked better than bad 1080p video on any screen and resolution. I have a 43" 4k monitor at ~1m distance and when I use the computer set up with 100% scaling it looks bad, I see pixelation... and "subpixelation". On a different computer connected to the same screen but something like 150% scaling it's like night and day difference. Everything looks smooth, perfect antialiasing. This is the money picture [0]. Above a certain distance any improvement is imperceptible. But don't compare compressed video on a screen, it will add quality issues that influence your perception. [0] https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41467-025-64679-2/MediaObjects/41467_2025_64679_Fig2_HTML.png https://media.springernature.com/full/springer-static/image/...
deleted 1y ago
[deleted]
sega_sai 1y ago
That gives 3 pixels per resolution element (assuming diffraction limit for 1cm diameter pupil). That sounds about right (see Nyquist frequency).
tonetegeatinst 1y ago
I would argue that color accuracy is under valued. Having a high resolution monitor is great, its even become semi affordable. But color accuracy can be a pain point. This dosnt matter if your just coding, unless you really care how realistic that code looks....but to anyone doing video or photo manipulation or front end design it can be a deal breaker.
- 4kchiefofstaff 1y ago
  I bought a while back a calibration device and calibrated my displays. I always buy good displays (ISP, high resolution, good test results) and the calibration was very very good out of the box. I sold the calibration device after. If you don't have to provide pin point accuracy from display to the industry level printer with color profile, you will not need this if you don't buy cheap.
ksec 1y ago
This is again showing with distance for TV viewing, we can see difference above 4K but barely touches 8K. Hence that is why I have been saying for close to 10 years now we should have settle on 6K with HDR as default. It seems after the failure of 3D and 8K the industry doesn't seems to care about anything anymore.
nadnad 1y ago
They also released a display resolution calculator related to the paper https://www.cl.cam.ac.uk/research/rainbow/projects/display_calc/ https://www.cl.cam.ac.uk/research/rainbow/projects/display_c... It also includes a useful Resolution limit matrix table for common resolutions/screen sizes

65 points by bookofjoe 1y ago

This is helpful for estimating how much higher display resolutions are still perceivable and when we enter the territory of "marketing bullshit". For example: - 40 cm view distance (e.g. smartphone): 300 ppi is roughly the maximum that's useful - 100 cm (e.g. desktop monitor): about 200 ppi https://www.nature.com/articles/s41467-025-64679-2/figures/2 https://www.nature.com/articles/s41467-025-64679-2/figures/2

cubefox 1y ago
About 15 cm view distance for smartphones is pretty normal for me (shortsighted with glasses) on websites where the text is very small, e.g. Hacker News.
- samat 1y ago
  I’ve started using text scaling on HN (Cmd++ on Mac, available on mobile, too) and it’s much easier to read and pleasant to the eye this way.
  - cubefox 1y ago
    Oh, that's a great idea. I see Firefox also has this in the settings under Accessibility. I guess I never looked there because I don't think of myself as disabled. (Maybe I should.)
    - bombcar 1y ago
      More and more - especially on Apple products - Accessibility is the "customization" menu, not the "disabled support" it used to be. Size increases, animation decreases (when your iPhone is getting old, turn off animation and behold it operating super fast!), etc can all be found there. I zoom websites until they "feel right" which is usually something close to "they are as wide as the window I have them in" - HN is a few taps up from "actual size".
    - trenchpilgrim 1y ago
      given enough time we all become disabled
trenchpilgrim 1y ago
I use my phone way closer than 40cm all the time...
- dev_hugepages 1y ago
  You may have untreated myopia, or need to use a bigger font size (HN is guilty of this!)
  - trenchpilgrim 1y ago
    No I just sometimes use my phone while lying down lol
noosphr 1y ago
I remember those numbers being a third that 20 years ago. Either we have evolved brand new eyes without noticing or you are just talking about the current state of the art like it's the limit of human vision. Put another way look at 300ppi prints and 1200ppi prints. The difference is night and day at 30 cm viewing.
- ncruces 1y ago
  ppi pixels ≠ dpi dots You don't need 1200ppi for a nice 1200dpi print; even 300ppi may be enough.
  - adrian_b 1y ago
    For printing photos, you are right that a 300 ppi printer is better than an 1200 dpi printer. On the other hand, for printing text, an 1200 dpi printer has the quality of an 1200 ppi printer. Many well-designed traditional typefaces have relied on optical effects caused by details that require for being printed a resolution higher than that at which the human eye can distinguish a set of bars from an uniform background (which is the object of TFA). For instance, in some typefaces the edges of the strokes are concave or convex, not straight, which could be rendered in a computer display only by either a much higher resolution or by more sophisticated pixel preprocessing methods (in order to simulate the effect on the eye). Whenever such typefaces are displayed at a lower resolution, i.e. on computer monitors, they are very noticeably uglier than when printed on paper by traditional metal printing methods or even by a high-resolution laser printer.
    - cubefox 1y ago
      A 1200 ppi display can use anti-aliasing, e.g. grey scale edges on text, while a 1200 dpi printer can't, I'm pretty sure. So the former has better quality.
jl6 1y ago
Higher ppi on mobile is still useful if it enables “manual zoom” (i.e. move your head closer). I do this with Google Sheets on mobile all the time, as I like to have a lot of the sheet displayed at once to see the overall structure, and then peer closer to read the text.
adrian_b 1y ago
You want to say "the minimum that is useful", because you want a resolution at least equal with that, to not see the pixel structure. A 27" monitor has a height around 17", i.e. about 43 cm, and for watching a movie or anything else where you look at the screen as a whole the recommended viewing distance is twice the screen height, i.e. about 86 cm. At this distance, the resolution needed to match the human vision is provided by a height of slightly less than 3000 pixels by this study, but by about 3300 pixels by older studies. In these conditions you are right, the minimum acceptable resolution is around 200 ppi. This means that a 27 inch 5k monitor, with a resolution of 2880 by 5120 pixels, when viewed from a distance twice its height, i.e. about 86 cm (34 inch), provides a resolution close, but slightly less than that of typical human vision. (That viewing distance that is double the height corresponds to the viewing angle of camera lenses with normal focal length, which has been based on studies about the maximum viewing angles where humans are able to perceive a correct perspective when looking at an image as a whole.) However, when not watching movies, but working with text documents, you normally stay closer to the monitor than that, so even a 5k monitor is not good enough (but an 8k monitor may be enough, so that might be the final monitor resolution, beyond which an increase is useless).

edelbitter 1y ago

One would expect the results to be highly correlated to corrected vision which is all over the place.. but they get suspiciously tightly grouped results. Did they maybe not measure how many pixels we can see.. but rather how laughably bad COTS IPS are at contrast, as the examined pattern approaches their resolution? I wonder what happens if you repeat that with a reasonably bright 16K OLED.

jdubb 1y ago

There's this classic by VSauce about the same topic: https://www.youtube.com/watch?v=4I5Q3UXkGd0 https://www.youtube.com/watch?v=4I5Q3UXkGd0

Terr_ 1y ago
I hate the fact that my very first reaction is: "That just got bulldozed."

drnick1 1y ago

Some people still say that 1080p is plenty, whether for reading text or watching videos (including gaming), but anyone who has used a 4K monitor knows that text looks far clearer and games look far more realistic and detailed at 4K. And the same will probably be true when 4K becomes truly mainstream on desktops.

fnands 1y ago
Yeah, I think diminishing returns kick in at some point. Going from 1080p to 1440p feels like a huge improvement. Going from 1440p to 4k (aka 2160p) is a little bit sharper. I don't think the jump from 4k to 8k will improve things that much.
- bombcar 1y ago
  I can tell the difference between 1080p (or upscaled 1080p) and 4k on a 50" screen at "living room" distances, but it's nowhere near as obvious as SD to DVD was. At "laptop" screen distances the difference between my Retina display and non-retina external monitors is quite noticeable; so much so that I run 4k in 1080p mode more and more. 8k is going to require those curved monitors because you'll have to be that close to it to get the advantage.
  - ant6n 1y ago
    DVDs are SD, with 480 pixels of resolution for ntsc.
    - bombcar 1y ago
      Yeah I meant VHS → DVD (which was noticeable), and also SD → HD (1080p) which was again noticeable.
  - close04 1y ago
    > I can tell the difference between 1080p (or upscaled 1080p) and 4k Are you talking about the resolution of the video or of the screen itself? Lower resolution video looks worse also because of the compression. I saw bigger difference from video compression than from screen resolution. E.g. good 1080p video looked better than bad 1080p video on any screen and resolution. I have a 43" 4k monitor at ~1m distance and when I use the computer set up with 100% scaling it looks bad, I see pixelation... and "subpixelation". On a different computer connected to the same screen but something like 150% scaling it's like night and day difference. Everything looks smooth, perfect antialiasing. This is the money picture [0]. Above a certain distance any improvement is imperceptible. But don't compare compressed video on a screen, it will add quality issues that influence your perception. [0] https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41467-025-64679-2/MediaObjects/41467_2025_64679_Fig2_HTML.png https://media.springernature.com/full/springer-static/image/...

deleted 1y ago

[deleted]

sega_sai 1y ago

That gives 3 pixels per resolution element (assuming diffraction limit for 1cm diameter pupil). That sounds about right (see Nyquist frequency).

tonetegeatinst 1y ago

I would argue that color accuracy is under valued. Having a high resolution monitor is great, its even become semi affordable. But color accuracy can be a pain point. This dosnt matter if your just coding, unless you really care how realistic that code looks....but to anyone doing video or photo manipulation or front end design it can be a deal breaker.

4kchiefofstaff 1y ago
I bought a while back a calibration device and calibrated my displays. I always buy good displays (ISP, high resolution, good test results) and the calibration was very very good out of the box. I sold the calibration device after. If you don't have to provide pin point accuracy from display to the industry level printer with color profile, you will not need this if you don't buy cheap.

ksec 1y ago

This is again showing with distance for TV viewing, we can see difference above 4K but barely touches 8K. Hence that is why I have been saying for close to 10 years now we should have settle on 6K with HDR as default. It seems after the failure of 3D and 8K the industry doesn't seems to care about anything anymore.

nadnad 1y ago

They also released a display resolution calculator related to the paper https://www.cl.cam.ac.uk/research/rainbow/projects/display_calc/ https://www.cl.cam.ac.uk/research/rainbow/projects/display_c... It also includes a useful Resolution limit matrix table for common resolutions/screen sizes