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Comment by amoss | Hacker News Reader

Could you expand on your numbers a little?

Assuming 4k resolution per eye and 120 degree FoV would give 3840*2/120 = 64 ppd.

Using the link that you gave a 4k screen at 60cm is 73 ppd, so it is reasonably close.

Apple haven't said what the FoV is yet, so I'm guessing 120 based on the pi-max and an early impressions video from mkbd. The horizontal range isn't clear either: 23 megapixels would be about three 4k screens so it depends on the overlap region between the eyes.

It's not that far off 4k, and when sitting that close to a 28" 4k screen I find the pixels barely noticeable, i.e. I can see them if they are aliased but would not notice them when the colour gradient is smooth.

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Based on your followup post, I think you're confused. Binocular overlap doesn't magically give you double the perceived resolution. If it worked that way, everyone would have a way higher PPD, but it doesn't and they don't. For a naive calculation on resolution you should just use the per eye resolution.

As mentioned resolution on the centroid may be higher depending on the lens design, but there's so much dependent on the rendering pipeline and the optics that I don't think it's worth doing more than ballparking. If you're interested in HMD displays, Oliver Kreylos has posted a lot on resolution measurements over the past few years:

* Optical Properties of Current VR HMDs http://doc-ok.org/?p=1414

* Measuring the Effective Resolution of Head-mounted Displays http://doc-ok.org/?p=1631

* The Display Resolution of Head-mounted Displays http://doc-ok.org/?p=1677

* The Display Resolution of Head-mounted Displays, Revisited http://doc-ok.org/?p=1694

Ha, significantly more complex than I realised. Thanks for the collection of links, very interesting reading.

With stereoscopic displays you don't get to multiply by 2, so your calculation is 32pp°.

If you think about a monitor in front, each pixel is seen by both eyes, but the headset is giving one 4k display to each eye.

Since your brain fuses the images from both eyes, you'll get a slightly higher effective resolution from the two displays than from a single display.

It depends on the amount of binocular overlap: https://www.roadtovr.com/understanding-binocular-overlap-and...

The correct number is somewhere between a multiplier of 1 and 2 depending on the setup of the display. But 2x 4k screens is only 16 megapixels, and so it also depends on where the other 7 megapixels are.

I can't edit this comment after 5 days but anybody coming along and find this - the multiplier is very close to 1. Go up a bit and find the sibling comment with the four links. Very good explanation of the difference between the monocular binocular FoV is buried within.

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