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Comment by ezluckyfree

5 years ago

I'm typing this on a 4k, 32" monitor, which is 137.68 DPI, but I also have a Dell XPS 15, which is 4K and 15", 293.72 DPI, and the difference in sharpness is astounding.

The other problem with hidpi scaling (200%) at 4k 32", is that everything is huge, and you lose a lot of screen real estate.

Honestly I think 8k 36" is the sweet spot.

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.

  • >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.

    • 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...

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  • >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.

  • > 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)

Why scale it if you think that makes me everything huge? I don't do the scaling and enjoy the extra real estate.

  • Because then you lose the sharpness, and the extra real estate is too much, so everything is both less sharp AND tiny.

  • I don't scale it, but then I lose the text sharpness. I would like both.

    • You could use bitmap fonts to get truly sharp text. I'm a big fan of terminus at 9pt. It makes non-bitmap fonts look blurry and awful by comparison. A real shame that Pango broke bitmap support and your choice of terminal emulator and other stuff is limited now.

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    • To keep the same pixel density you'd need an 8K at 30" or 10K at 36". I'm sure we'll get there but not anytime soon, at least not at prices almost anyone would be willing to pay, or not without sacrificing other specs that you surely want.

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There's settings other than 100% and 200%. Set it to 125%. Or 150%.

  • That is not the same. Non-integer scaling results in worse sharpness because of the way it needs to be implemented.

    See eg: https://tonsky.me/blog/monitors/

    • That's not true at all. Fonts & other vector-based graphics scale to any resolution just fine.

      The myth of 1x, 2x, and 3x being "preferred" is just an Apple-ism because their UI toolkit is pixel-based. That's a flaw in their toolkit, not an inherent technical constraint. Combined with then Apple scaling it yet again after it's rendered.

      Other platforms are not nearly as badly designed.

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    • You are not getting any 'sharpness benefit' if your 4k display is showing an upscaled 1080p image.

      All applications i use on windows support scaling natively, and provide crisp text at 150%. It's not 2010 any more, this is a solved problem. Anything that doesnt should be killed with fire.

I have the same displays as you- Dell 4k @ 15" and currently using a 32" 4k (I sit 2ft away from it). I also have a Macbook Pro 16 (3072×1920). I honestly don't see a substantial difference between any of them, and I'm generally pretty picky about resolution.

  • Right but if you scale the 32" so you get the hidpi sharpness (and put it far away), you lose the real-estate that you could have on a 32" screen.

I use 4K 32" with scaling at 100% and it seems totally fine. Lots of real 15-17" laptop screen at 4K makes no sense to me as I can't use 100% as the text size becomes too small.

  • Right, the whole idea is that you use 200% and get that really crisp text.

    • What I have already feels crisp enough and since I do a lot of programming I'd rather see more lines of code than increase scaling for no real benefits. As a matter of fact one of the 2 4K monitors on my desk is in portrait mode just for that.

You shouldn't be as close to the laptop screen as to the big monitor. And at larger distances the pixel densities can be lower.

  • This is the argument that HiDPI displays are pointless if you're not very close to the monitor, and if you've used a retina display, you know that there is absolutely a difference.

    • You probably hold your phone about 30-40cm from your face. You probably look at your laptop screen at 50-60. You should be at least 75cm it not 90 or 100cm away from a big monitor.

      I'm not convinced the difference is obvious.

  • Did you say that backwards? On my lap, the screen of my laptop is 17"-20" from my face. At a desk, the monitor is usually about 28" from my face.

    • Yeah, I might have :-)

      You should be farther from your monitor than you are from your laptop.