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Comment by HPsquared | Hacker News Reader

What's the definition of "Retina grade"? Surely the eyes ability to distinguish pixels depends on how far the screen is.

An average 4K TV at a typical viewing distance is going to be impossible to distinguish the pixels. Same with a typical 4K monitor, depending on the size and viewing distance.

EDIT: A 27" 4K display at 60 cm viewing distance (53° horizontal FoV) has 73 pixels per degree (ppd).

A Retina equivalent display is anything above 60 ppd (i.e. 1 arcminute per pixel) as far as I can tell.

Calculator here: https://qasimk.io/screen-ppd/

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The problem with a 4K display is that if you run it at a pixel ratio of 2, you're only getting effectively the screen real estate of a 1080p display. For me, the difference between the real estate of 1080p vs. 1440p is significant, but to get 1440p of real estate at a pixel ratio of 2 you need a 5K display.

For programming work I'm currently using one of those ultrawide 3440x1440 monitors, which is just a wider version of 1440p (which is 2560x1440). My ideal monitor at the moment would be this 3440x1440 monitor but with a pixel ratio of 2. This should be relatively feasible for reasonably-spec'd machines to drive and to manufacture (it would still be significantly fewer pixels than an 8K display), but AFAIK nothing like this exists on the market.

Unfortunately, 5K 27" displays went nowhere. Around 5-6 years ago I was hoping for that to become the standard resolution for 27", instead of UHD (billo 4K), but alas. I believe that one LG display is literally the only 5K 27" display on the market now. And that's of course a 60 Hz panel, like all other 5K 27" have been, and it's an LG IPS on top, so not exactly the best image quality you can imagine.

That was my hope as well. I thought Apple's manufacturing scale would make the displays common. I still have one of the early 27" 5K iMacs and I'm sad that I can't just use it as an external monitor. I've heard nothing but bad things about the LG 5K display, and it's pretty nutty that it costs like 75% what a new 27" iMac costs.

> I've heard nothing but bad things about the LG 5K display…

I've been using one for a year. It would be hard to use anything else.

Most laptops are not capable of pushing 5K for external displays. Even my '18 MBP can't handle a 4k monitor at 60Hz (at least, I couldn't get it to work).

So the market for these is limited to people with desktop workstations or pretty high-end laptops. Which is probably why they aren't going anywhere.

> Even my '18 MBP can't handle a 4k monitor at 60Hz

I bet you were trying to use HDMI or an adapter? If so that's a known issue with the transport mechanism, not the laptop. My '17 MBP can do two 4k external displays at 60Hz on top of the internal display using displayport, so yours can definitely do one.

This is a good reference. Note that it's from 2016: https://9to5mac.com/2016/11/17/macbook-pro-external-display-...

It doesn't help that you can drive 2 4K displays but only 1 5K display on most Thunderbolt hardware.

I've got something that's most of the way there and imho quite adequate: a 5k2k, at 5120x2160.

So that's a 1080p widescreen at a pixel ratio of 2, and maybe it's because my eyes aren't as young as they were, but that's perfect for me. Certainly renders any font I throw at it as crisp as you please.

It's the MSI Prestige, if you're curious.

On my windows 10 systems, I set scaling to 150%. Is that not an option with other OSs?

OSX does this too, but instead of a % scale, scaling slider has detents for "look like" a different, standard resolution. I.e., native is 3072x1920 but it is scaled to look like 2048x1280

The issue mainly stems from the way macOS does UI scaling.

To get UI elements the right physical size for a 27” 4K screen it would render to a 5120x2880 (i.e. 2560x1440@2x) framebuffer then do a non-integer scale back down to 4K. Sharper than 2560x1440 to be sure, but you can notice the blurring it introduces.

Basically all large hi-DPI monitors for Macs are a compromise except the Pro Display, which is like $5000.

When the pixels are so dense, that using the monitor at its typical viewing distance makes pixels indistinguishable. But not just in the sense that you cannot see that your view is pixelated, rather in the sense that packing the pixels any denser wouldn't make a difference.

Quality desktop monitors viewed at their typical distance do not look pixelated, e.g. you rarely are able to see individual pixels especially if proper antialiasing is used, but they do still almost always have a lack of sharpness that could be corrected with a denser display.

On retina smartphones, making the pixels denser wouldn't make the image look any sharper from a typical viewing distance. Once you achieve that, I'd say it's "retina-grade".

> On retina smartphones, making the pixels denser wouldn't make the image look any sharper from a typical viewing distance.

If that were true, there would be no reason for Apple to switch from 326ppi to whatever they use now for new phones. The real point where this stops making a difference is likely somewhere much higher, just like with framerates. That doesn't mesh well with their luxury electronics marketing narrative, though.

Yeah, and digital camera manufacturers aren't adding megapixels for nothing and processor makers don't chase higher clock speeds for nothing, right? Because why would they keep adding pixels and increasing the clock frequency just to make the tech numbers look more impressive in order to sell more electronics? Yes, sounds pretty ridiculous.

Now of course, maybe the new retina screens appear slightly sharper if you have exceptionally good eyesight, but I have long ago stopped seeing any improvement in sharpness of smart phone displays. The screens do look better in terms of better colours, contrast etc, but at a typical distance with an individual with normal eyesight, adding more pixels does pretty much nothing at this point.

Ya, why would Tesla make a car that can go 0-60 in 2 seconds if that wasn't a noticeable improvement in usefulness?

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