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Comment by GuB-42

5 years ago

DPIs don't mean anything unless you factor in viewing distance.

In fact, it is common to recommend a vertical viewing angle of 30 degrees. Not more as it tends to increase eye fatigue and neck pain. If you follow that recommendation, what matters is the definition (the number of pixels), not the resolution in DPI.

So, let's run a few calculations. The "retina" resolution is based on a pixel size of 1 arc-minute, that's 20/20 vision, at 30 degrees, that's 1800 pixels. 4k is 2160 vertical, so that's about the limit of human vision. So, basically, 4k is what you want at any size.

8k is not useless but you are pushing the boundaries here. In order to notice it, you need perfect, over 20/20 vision, high luminosity and high contrast. Beyond 8k, you enter superhuman territory, with an exception: you can notice discontinuities at a much higher resolution (vernier resolution), but it only matters if you don't have anti-aliasing. And of course, high contrast, luminosity and perfect vision.

There are exception. For example there is a limit on how close a screen can be, so having 4k on a tiny smartphone screen is mostly useless. The other end of the spectrum would be VR, with fields of view over 100 degrees, 8k per eye is considered a minimum for an immersive experience.

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GuB-42

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ezluckyfree  5 years ago

>So, let's run a few calculations. The "retina" resolution is based on a pixel size of 1 arc-minute, that's 20/20 vision, at 30 degrees, that's 1800 pixels. 4k is 2160 vertical, so that's about the limit of human vision. So, basically, 4k is what you want at any size.

No, because I don't want to move my 32" monitor further away to get that 30 degree viewing angle. The reason I have a 32" monitor for work is to have more screen real estate. A 30 degree viewing angle works for watching movies and stuff, but when I use it for coding, I essentially have multiple 30 degree viewing (on-screen) windows.

You might say "ok well just get two or three monitors", but that isn't the same either. Besides the space between the monitors, with one large monitor I can subdivide my screen space in any way depending on what I'm doing, where each window has a 10-30 degree viewing angle or whatever.

>you can notice discontinuities at a much higher resolution (vernier resolution), but it only matters if you don't have anti-aliasing.

That's just not true though. It does matter even with antialiasing, the difference is clear. In particular, the dell xps 15 2019 has a ~290 dpi OLED, which has high contrast.

  • GuB-42  5 years ago

    30 degrees vertical is actually a recommendation for work[1], not for movies. If you look around for guide about ergonomics, you will often see that 30 degrees figure, or "top of the screen at eye level, center 15 degrees down", which mean the same thing.

    For movies, THX recommends a 36 degrees horizontal viewing angle[2], which is about 20 degrees vertical. Recommendations vary, sometimes it is 30 degrees, sometimes it is 40, but always horizontal.

    Now, no one will force you. If you prefer to have a very large screen right up your nose, that's your choice, and maybe your work environment calls for it. But it is just not what it is generally recommended and I would put it into the "exception" category. And sure, in that case, increased resolution is good.

    As for antialiasing, it will not make the image sharper, quite the opposite in fact. However, if your resolution is so that it is over your visual acuity (you can't distinguish between 2 thin parallel lines and 1 thicker line), antialiasing will take care of superaccuity. That's the ability of your brain to use image processing techniques to detect jaggies that are finer than what you eye can see. If you have good vision and a 4k monitor closer to you than the recommended distance, it is normal to see the difference even with anti-aliasing turned on.

    [1] https://www.viewsonic.com/library/business/best-computer-scr...

    [2] https://www.thx.com/questions/thx-certified-screen-placement...

    • wtallis  5 years ago

      If the recommended horizontal viewing angle for a movie is 36 degrees, why is it hard for you to understand wanting a desktop PC display with significantly larger field of view, given that large PC displays are used subdivided into multiple windows? There's real usability value for a PC display that extends further into your peripheral vision than a movie screen, because you don't actively watch the whole PC screen at once.

coldtea  5 years ago

>DPIs don't mean anything unless you factor in viewing distance.

Between phone, table, and laptop, monitor, yes.

But when speaking of monitors alone, it's not that relevant an observation in practice, since most monitors, whether 27", or 32", or 24" are seen from more or less the same distance.

0-_-0  5 years ago

> 4k is 2160 vertical, so that's about the limit of human vision.

This is false. Misalignment of borders can be detected with a precision up to 10 times better than visual acuity [0], therefore your numbers should be multiplied by 10, meaning 40K is the optimal screen resolution, or 80K for people with particularly good vision.

[0] https://en.wikipedia.org/wiki/Hyperacuity_(scientific_term)