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ImSpartacus
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### Retina Display? Look on your desk.

Arclight got me thinking in this thread. At what viewing distance can we get the iPhone 4's Retina effect in our current desktop monitors?

It turns out that you need to be exactly three feet from a 1920x1080 24" monitor to experience the Retina effect of the iPhone 4. Not bad for a common monitor that can be had for less than \$200, eh?

More combinations of screen size, viewing distance and the subsequent required rows of square pixels can be found here. Remember 1080p has 1080 rows of pixels, 1440p has 1440 rows and 4K (quad 1080p) has 2160 rows. The chart is only accurate for 16:9 resolutions.

Would someone mind checking my work? My results seem too good to be true.

ImSpartacus wrote:
I used this new iPad slide and slightly modified formulas from this wikipedia page to find what resolution would yield Retina-i-ness on a screen of any size and aspect ratio.

Long story short,

sqrt(D^2H^2/(W^2+H^2))/2(d)tan(a/2)

is the height (short side) of this resolution and the width (long side) of the resolution can be found by multiplying the width and the aspect ratio. Variable definitions can be found at the two sources.

For a 24" 16:9 monitor viewed at 30" that has as much Retina-i-ness as the iPhone 4, we only need 1292.91 rows of pixels. So today's \$200 1080p monitors are almost there. 1440p in a 24" 16:9 at 30" would be more Retina-y than the iPhone 4!

From a different perspective, a 24" 1080p monitor has as much Retina-i-ness as the iPhone 4 from 36" away (actually, you only need 1077 pixels at 36", so 1080 does the job).

So you'll be pleased to hear that you already have a retina display on your desk. Just get three feet away from it.
Last edited by ImSpartacus on Wed Mar 28, 2012 12:40 pm, edited 2 times in total.

Ari Atari
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I feel like it will always be a bad comparison. I've got a 25'' 1920x1200 display and a Droid 1. If I want to watch a 480p youtube video, it seems like it always looks better on the Droid.

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Ari Atari wrote:
I feel like it will always be a bad comparison. I've got a 25'' 1920x1200 display and a Droid 1. If I want to watch a 480p youtube video, it seems like it always looks better on the Droid.

If you play it at 1:1 size and push your face closer, it'll look pretty good too lol. It's just that when you blow up the image, all the artifacts and defects are made larger and more visible.

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No,no. I'm not talking about expanding it full screen. I'm talking about 480p 1:1 on the desktop screen, so that it only takes up a small fraction of the screen.

ImSpartacus
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Ari Atari wrote:
No,no. I'm not talking about expanding it full screen. I'm talking about 480p 1:1 on the desktop screen, so that it only takes up a small fraction of the screen.

Going from a phone to a desktop monitor, viewing distance triples and pixel density is cut in half. Both changes reduce perceived detail, which decreases the viewing quality for a 1:1 scaled video.

When you move from a smaller screen (close viewing) to a larger screen (far viewing), pixel density doesn't have to remain constant (as shown above), but total pixel count must increase. Since you're watching a 480p clip on both screens, the closer view will look better every time.

That's why HDTV existed. TV size got too big, people thought they could sit further, but they needed more pixels. Also the reason Super Hi Vision (HDTV 2.0, 4x1080p) is necessary. It's not for current TVs, it's for 65"+ TVs. The big 80" TVs need more pixels just to maintain viewing quality just like your computer monitor needs a video with more pixels to compete with video on your phone.
Last edited by ImSpartacus on Wed Mar 28, 2012 12:11 pm, edited 1 time in total.

Damage
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### Re: Retina Display? Look on your desk.

Man, these comparisons always bug me.

The assumed viewing distances are my first beef.

Who sits three feet from their monitor for real work? Isn't that a long way? Take a quick estimate: how far do you sit?

The fact there are assumptions about the clarity of one's vision based on an average person's perception is another problem. My eyesight needs a lot of correction, but it sure seems I can see better with correction than the folks making these estimates. I can make out pixels and jagged edges way too easily.

Even if one *did* sit that far from the screen generally, one does tend to lean in when needing to see more detail, just like you'll hold a piece of paper or a tablet closer to your face. When that detail isn't available, it's disappointing and unhelpful.

Bottom line: I can perceive the limits of my desktop display readily, regardless of any math you're doing. Sub-pixel antialiasing helps a lot, but isn't a cure-all. Pretty sure I'm not some weird outlier in this regard. I'm starting to think the folks doing these estimates may be a bit vision-impaired, though. Or, you know, their assumptions are bad.

No offense intended, and it is a fun exercise. Just not buying the results.
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ImSpartacus
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### Re: Retina Display? Look on your desk.

Damage wrote:
Who sits three feet from their monitor for real work? Isn't that a long way? Take a quick estimate: how far do you sit?

I measured two and a half feet for myself, so it wasn't too far off for me. The US department of labor suggests 20-40" as a healthy viewing distance. 36" is definitely on the upper end and is probably unrealistic for many users, but it isn't a completely outlandish usage case.

Damage wrote:
The fact there are assumptions about the clarity of one's vision based on an average person's perception is another problem. My eyesight needs a lot of correction, but it sure seems I can see better with correction than the folks making these estimates. I can make out pixels and jagged edges way too easily.

Whether it's false advertising or not, the iPhone 4's 'Retina' screen has certainly caught on with many users and critics. I think it's fair to compare your desktop experience to it, regardless if it actually achieves its goal.

Damage wrote:
No offense intended, and it is a fun exercise. Just not buying the results.

It's all about the assumptions you make. Assuming that an actual person could productively sit 36" away from their PC and that the iPhone 4 really does have a 'Retina' effect are both admittedly strong assumptions. But the point isn't to get you to move your monitor further back on your desk, it's that we don't immediately need expensive 4K monitors (except at like 27"+) to achieve the same 'Retina' effect as the vaulted iPhone 4. I should've more clearly mentioned that. I was (errr am) more worried that I made a calculation mistake in creating that little formula. But I appreciate the feedback, thank you.

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### Re: Retina Display? Look on your desk.

ImSpartacus wrote:
Damage wrote:
Who sits three feet from their monitor for real work? Isn't that a long way? Take a quick estimate: how far do you sit?

I measured two and a half feet for myself, so it wasn't too far off for me. The US department of labor suggests 20-40" as a healthy viewing distance. 36" is definitely on the upper end, but it isn't an absurd usage case.

For me, typically 24-27" to my work monitors. At home, about 20-24" if I'm doing work and more like 30" when gaming since I like to slouch back a bit.
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### Re: Retina Display? Look on your desk.

ImSpartacus wrote:
Damage wrote:
The fact there are assumptions about the clarity of one's vision based on an average person's perception is another problem. My eyesight needs a lot of correction, but it sure seems I can see better with correction than the folks making these estimates. I can make out pixels and jagged edges way too easily.

Whether it's false advertising or not, the iPhone 4's 'Retina' screen has certainly caught on with many users and critics. I think it's fair to compare your desktop experience to it, regardless if it actually achieves its goal.

Let me clarify. My desktop display looks substantially coarser and less desirable than either an iPhone 4 or a third-gen iPad does in normal use. I am not very interested in the specifics of the validity of "retina" claims for any of these things, but there is indeed a substantial perceptive difference between these high-DPI devices on the one hand and the current best desktop and laptop displays on the other. Since we're reading text and such on them, the limits of my perception if I were strapped in and not allow to get any closer than 36" from my display seems kind of irrelevant.

Heck, I think my eyes would relax and allow me to sit back further if the display were crisper.
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ImSpartacus
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### Re: Retina Display? Look on your desk.

ludi wrote:
ImSpartacus wrote:
Damage wrote:
Who sits three feet from their monitor for real work? Isn't that a long way? Take a quick estimate: how far do you sit?

I measured two and a half feet for myself, so it wasn't too far off for me. The US department of labor suggests 20-40" as a healthy viewing distance. 36" is definitely on the upper end, but it isn't an absurd usage case.

For me, typically 24-27" to my work monitors. At home, about 20-24" if I'm doing work and more like 30" when gaming since I like to slouch back a bit.

Good to know. I'm building a quick spreadsheet. I'm using 18-36" in 2" increments. It'll be up in ten minutes or so.

EDIT, Finished!

Damage wrote:
ImSpartacus wrote:
Damage wrote:
The fact there are assumptions about the clarity of one's vision based on an average person's perception is another problem. My eyesight needs a lot of correction, but it sure seems I can see better with correction than the folks making these estimates. I can make out pixels and jagged edges way too easily.

Whether it's false advertising or not, the iPhone 4's 'Retina' screen has certainly caught on with many users and critics. I think it's fair to compare your desktop experience to it, regardless if it actually achieves its goal.

Let me clarify. My desktop display looks substantially coarser and less desirable than either an iPhone 4 or a third-gen iPad does in normal use. I am not very interested in the specifics of the validity of "retina" claims for any of these things, but there is indeed a substantial perceptive difference between these high-DPI devices on the one hand and the current best desktop and laptop displays on the other. Since we're reading text and such on them, the limits of my perception if I were strapped in and not allow to get any closer than 36" from my display seems kind of irrelevant.

Heck, I think my eyes would relax and allow me to sit back further if the display were crisper.

So you're saying that viewing distance is a constantly moving target and it's meaningless to try to tie it down to anything but a wide range of potential distances? You're probably correct.

That assumption justifies the rumored 'Retina' Macbook Pros' extreme quad resolutions, since they would could be called 'Retina' from 15" away (12" for the MBP17). I think that would satisfy me, lol!
Last edited by ImSpartacus on Wed Mar 28, 2012 1:14 pm, edited 2 times in total.

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### Re: Retina Display? Look on your desk.

So I don't get to lean any closer than 18"?
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### Re: Retina Display? Look on your desk.

Damage wrote:
So I don't get to lean any closer than 18"?

At my age 27" is too close at times on a 1680x1050 2007WFP. I've been fighting it for a few years now but in this annual optometry cycle it's either bifocal contacts or readers.
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ImSpartacus
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### Re: Retina Display? Look on your desk.

Damage wrote:
So I don't get to lean any closer than 18"?

How's 8"?

Apple pegged their 3.5" phone viewing distance at 10", so I don't think it'd be accurate to go any closer than 8" since we're basing this off the iPhone 4 at 10". I know I use my phone a lot closer than 10" sometimes.

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### Re: Retina Display? Look on your desk.

I sit almost exactly 36" away. About 35.5" actually. That is from a 1920x1200 24" screen. I should also note that I have 20-10 vision naturally though. At my normal distance, I can just make out pixelation in high contrast images. Sub pixel aliased fonts start to show pixelation at around 20". I looked at a friends "the new iPad" the other day. I simply cannot make out an individual pixel on the screen under normal circumstances. I loose the ability to focus before I can get close enough to the screen.

As far as the image quality on a bigger screen, think of it this way. As the screen size increases, you sit further away. Assume you move back linearly as the screen size grows. Each pixel continues to take up approximately the same amount of your field of vision. The problem is that everything else around the display changes. At the extreme of, say, a jumbotron, you get a single pixel the size of a penny. Even ignoring the actual optical/physical properties of the eye, so long as you have something to reference to, your brain is going to clue in on the fact that you are looking at really big pixels from far away and you will perceive it as lower quality.

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### Re: Retina Display? Look on your desk.

SecretSquirrel wrote:
I sit almost exactly 36" away. About 35.5" actually. That is from a 1920x1200 24" screen. I should also note that I have 20-10 vision naturally though. At my normal distance, I can just make out pixelation in high contrast images. Sub pixel aliased fonts start to show pixelation at around 20". I looked at a friends "the new iPad" the other day. I simply cannot make out an individual pixel on the screen under normal circumstances. I loose the ability to focus before I can get close enough to the screen.

As far as the image quality on a bigger screen, think of it this way. As the screen size increases, you sit further away. Assume you move back linearly as the screen size grows. Each pixel continues to take up approximately the same amount of your field of vision. The problem is that everything else around the display changes. At the extreme of, say, a jumbotron, you get a single pixel the size of a penny. Even ignoring the actual optical/physical properties of the eye, so long as you have something to reference to, your brain is going to clue in on the fact that you are looking at really big pixels from far away and you will perceive it as lower quality.

--SS

That's pretty much what I observe on my 24 inch. That being said on my 15.6 1080p laptop I can't make out the pixels from a normal typing position, aka not leaning forward.
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ImSpartacus
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### Re: Retina Display? Look on your desk.

SecretSquirrel wrote:
As far as the image quality on a bigger screen, think of it this way. As the screen size increases, you sit further away. Assume you move back linearly as the screen size grows. Each pixel continues to take up approximately the same amount of your field of vision. The problem is that everything else around the display changes. At the extreme of, say, a jumbotron, you get a single pixel the size of a penny. Even ignoring the actual optical/physical properties of the eye, so long as you have something to reference to, your brain is going to clue in on the fact that you are looking at really big pixels from far away and you will perceive it as lower quality.

Can the brain make that distinction? I remember hearing about some overpriced glasses with LCDs in them that provided a 3D (one screen per eye, after all) image roughly equivalent to an 80" HDTV at 20" or something like that. It was just marketing, but I wonder if the brain can really estimate distances like that.

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### Re: Retina Display? Look on your desk.

ImSpartacus wrote:
SecretSquirrel wrote:
As far as the image quality on a bigger screen, think of it this way. As the screen size increases, you sit further away. Assume you move back linearly as the screen size grows. Each pixel continues to take up approximately the same amount of your field of vision. The problem is that everything else around the display changes. At the extreme of, say, a jumbotron, you get a single pixel the size of a penny. Even ignoring the actual optical/physical properties of the eye, so long as you have something to reference to, your brain is going to clue in on the fact that you are looking at really big pixels from far away and you will perceive it as lower quality.

Can the brain make that distinction? I remember hearing about some overpriced glasses with LCDs in them that provided a 3D (one screen per eye, after all) image roughly equivalent to an 80" HDTV at 20" or something like that. It was just marketing, but I wonder if the brain can really estimate distances like that.

The brain isn't so good at estimating distances, but it is really really good at noticing relationships. Ask someone how far away an object, especially one of fair distance, is and their ability to get the right answer is highly dependent on being able to relate it to known distances. The brain is very good at context. This is why optical illusions work. The context is set up to provide misleading cues to the brain. I suspect that if you took a 7" 1080p screen and a 65" 1080p screen and placed them relative to each other such that their images cover the same area of vision and then blocked off all surrounding cues, they would have very similar perceived quality.

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### Re: Retina Display? Look on your desk.

I sit roughly 27" away from my 27" displays. According to http://goo.gl/014bV that is roughly 89% Retina. I don't need glasses and everything looks good. If need be I'll bump up the text size in app. My 11.6 MBA gives me 87% of Retina.

While I love my 27" displays my 3rd gen iPad really does take display tech to a new level - there is a noticeable difference.
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ImSpartacus
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### Re: Retina Display? Look on your desk.

End User wrote:
I sit roughly 27" away from my 27" displays. According to http://goo.gl/014bV that is roughly 89% Retina. I don't need glasses and everything looks good. If need be I'll bump up the text size in app. My 11.6 MBA gives me 87% of Retina.

While I love my 27" displays my 3rd gen iPad really does take display tech to a new level - there is a noticeable difference.

Can you discuss it that way? It seems odd to consider a particular viewing experience as some percentage of 'Retina'. But I still don't have a firm handle on this material, so its to be expected.

I do like how the author of that spreadsheet leapfrogged the iPhone entirely and just went after the definition of 20/20 vision.

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### Re: Retina Display? Look on your desk.

ImSpartacus wrote:
Can you discuss it that way? It seems odd to consider a particular viewing experience as some percentage of 'Retina'. But I still don't have a firm handle on this material, so its to be expected.

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### Re: Retina Display? Look on your desk.

SecretSquirrel wrote:
I loose the ability to focus before I can get close enough to the screen.

I think we may have the answer right here. Typical distance is one thing, but people do shift positions while working, causing subtle detail shifts to be perceived, and sooner or later the user is going to lean in close to try and pick out something. The perceived quality of the screen will be affected by the discrete experiences that deviate from the average, not the average itself. (This is pretty much the same theory that TR has applied in its expanded video card review methodology.)

If the display is so dense that it exceeds the limits of the eye to detect pixelation at any usable viewing distance, the quality of the experience is no longer limited by those deviations.
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