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Is there any truth to the 300PPI limit?

Is there any truth behind Steve Jobs' claim that 300PPI was the cut-off for the human eye? Surely that's something that'd be scientifically verifiable? Or does no one care? ;) We're now approaching twice that number with some phones.

Most Useful Answer spruceyb  Apr. 1, 2014 at 15:49

Steve Jobs was good at hype. There's some truth to his statements regarding PPI but it's not the whole truth.

For a start it depends on peoples visual acuity but the average is 1 Arc minute.
Then it depends on the focal distance, average adult is no closer than 4 inches (test it yourself, by seeing how close your finger can get to your eye without losing focus).

So with these 2 measurements we can say the pixel size we could resolve is 0.0116 mm, now how many of those could we fit in an inch? Well, it's 876 ppi so that's the maximum for average people, but who is consuming visual media that close to their eyes?
Theoretically the maximum would probably be around 2190ppi for someone whose visual acuity is 0.4 arc minutes but finding people with such good eyesight is rare.

Now where Apple's Retina figure comes from is to do with printed media which is usually somewhere around 300ppi.
This is because most reading is done at least 1 foot away, at this distance the average eye resolves pixels size of 0.089mm and the amount of those we can fit into an inch is 300. Hence 300ppi.

So yeah, there are going to be some people who benefit from the higher ppi, but not many.

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spruceyb  Apr. 1, 2014 at 15:49

Steve Jobs was good at hype. There's some truth to his statements regarding PPI but it's not the whole truth.

For a start it depends on peoples visual acuity but the average is 1 Arc minute.
Then it depends on the focal distance, average adult is no closer than 4 inches (test it yourself, by seeing how close your finger can get to your eye without losing focus).

So with these 2 measurements we can say the pixel size we could resolve is 0.0116 mm, now how many of those could we fit in an inch? Well, it's 876 ppi so that's the maximum for average people, but who is consuming visual media that close to their eyes?
Theoretically the maximum would probably be around 2190ppi for someone whose visual acuity is 0.4 arc minutes but finding people with such good eyesight is rare.

Now where Apple's Retina figure comes from is to do with printed media which is usually somewhere around 300ppi.
This is because most reading is done at least 1 foot away, at this distance the average eye resolves pixels size of 0.089mm and the amount of those we can fit into an inch is 300. Hence 300ppi.

So yeah, there are going to be some people who benefit from the higher ppi, but not many.

JanSt / MOD  Apr. 1, 2014 at 16:19

Good answer, sprucey (as usual)...

I find other factors play an important role too, and most of them are also matters of personal preference etc... I e.g. never 'liked' Samsung's AMOLEDs. Has nothing to do with my dislike of Android. Even the Jet and their WinMo and WP handsets make me 'uncomfortable'... I can't look at them for long periods of time.
On the other hand: I really like Nokia's ClearBlack screens - even those of lesser resolution.

The iPhones' retina display again -a matter of taste. I personally like them. They 'appear' less artificial. Less 'flamboyant'.... But that is my perception. Not gospel.

matt101101 / MOD  Apr. 1, 2014 at 16:50

I do wonder about the 300ppi thing. That's based on an average person's eyesight, however iPhones (and other hi-tech phones) tend to be used by younger people, who, on average, have better eyesight than older people.

So the "average person", who Jobs was on about, probably isn't the same average person who is the average user of an iPhone. The actual "average person" is probably somewhere in their late 30's in a developed nation with a life expectancy in the high 70s, whereas I'd be surprised if the average user of an iPhone was over 25 (lets face it, pretty much every kid whose parents can afford to get them one, has one).

That and there's a clear difference in clarity between the display on the original HTC One (one of the highest PPI phones which isn't some Chinese obscurity) and an iPhone 4 and above.

Admittedly I have very good eyesight, well, according to my optician, but 20/20 vision is only being able to see, at 20 feet away, what a "normal" (direct quote from the American Optometric Association) person can see at 20 feet away. That must mean that lots of people have better than 20/20 vision, so can benefit from higher PPI displays.

spruceyb  Apr. 1, 2014 at 17:14

I do wonder about the 300ppi thing. That's based on an average person's eyesight, however iPhones (and other hi-tech phones) tend to be used by younger people, who, on average, have better eyesight than older people.

So the "average person", who Jobs was on about, probably isn't the same average person who is the average user of an iPhone. The actual "average person" is probably somewhere in their late 30's in a developed nation with a life expectancy in the high 70s, whereas I'd be surprised if the average user of an iPhone was over 25 (lets face it, pretty much every kid whose parents can afford to get them one, has one).

That and there's a clear difference in clarity between the display on the original HTC One (one of the highest PPI phones which isn't some Chinese obscurity) and an iPhone 4 and above.

Admittedly I have very good eyesight, well, according to my optician, but 20/20 vision is only being able to see, at 20 feet away, what a "normal" (direct quote from the American Optometric Association) person can see at 20 feet away. That must mean that lots of people have better than 20/20 vision, so can benefit from higher PPI displays.


At 0.4 arc minutes (this is pretty much the maximum for human VA), 1 foot away you'd get 720ppi,
0.4 arc minutes is about 20/8
For perspective, in a study of professional sportsmen highest recorded was 20/8.9

So it only becomes truly pointless when mobile displays are exceeding 720ppi

matt101101 / MOD  Apr. 1, 2014 at 21:22

I do wonder about the 300ppi thing. That's based on an average person's eyesight, however iPhones (and other hi-tech phones) tend to be used by younger people, who, on average, have better eyesight than older people.

So the "average person", who Jobs was on about, probably isn't the same average person who is the average user of an iPhone. The actual "average person" is probably somewhere in their late 30's in a developed nation with a life expectancy in the high 70s, whereas I'd be surprised if the average user of an iPhone was over 25 (lets face it, pretty much every kid whose parents can afford to get them one, has one).

That and there's a clear difference in clarity between the display on the original HTC One (one of the highest PPI phones which isn't some Chinese obscurity) and an iPhone 4 and above.

Admittedly I have very good eyesight, well, according to my optician, but 20/20 vision is only being able to see, at 20 feet away, what a "normal" (direct quote from the American Optometric Association) person can see at 20 feet away. That must mean that lots of people have better than 20/20 vision, so can benefit from higher PPI displays.


At 0.4 arc minutes (this is pretty much the maximum for human VA), 1 foot away you'd get 720ppi,
0.4 arc minutes is about 20/8
For perspective, in a study of professional sportsmen highest recorded was 20/8.9

So it only becomes truly pointless when mobile displays are exceeding 720ppi

So even half way between Jobs' 300ppi claim and the more realistic 720ppi absolute maximum you've got 510ppi, which probably isn't an unobtainable maximum for a lot of young people or people with above average eyesight.

It also explains why the 400ppi+ displays on modern high-end smartphones look noticeably better than the 300ppi+ displays on the iPhone 4 and above (and other lower resolution, popular phones such as the Galaxy S3).

awoodhall2003  Apr. 2, 2014 at 12:09

Bring in GoogleGlass...where it will be less than an inch...hmmm....

AhmadCentral  Apr. 2, 2014 at 12:39

Steve Jobs was good at hype. There's some truth to his statements regarding PPI but it's not the whole truth.

For a start it depends on peoples visual acuity but the average is 1 Arc minute.
Then it depends on the focal distance, average adult is no closer than 4 inches (test it yourself, by seeing how close your finger can get to your eye without losing focus).

So with these 2 measurements we can say the pixel size we could resolve is 0.0116 mm, now how many of those could we fit in an inch? Well, it's 876 ppi so that's the maximum for average people, but who is consuming visual media that close to their eyes?
Theoretically the maximum would probably be around 2190ppi for someone whose visual acuity is 0.4 arc minutes but finding people with such good eyesight is rare.

Now where Apple's Retina figure comes from is to do with printed media which is usually somewhere around 300ppi.
This is because most reading is done at least 1 foot away, at this distance the average eye resolves pixels size of 0.089mm and the amount of those we can fit into an inch is 300. Hence 300ppi.

So yeah, there are going to be some people who benefit from the higher ppi, but not many.


I like this answer!
Very well written!

spruceyb  Apr. 3, 2014 at 00:18

Bring in GoogleGlass...where it will be less than an inch...hmmm....

Google Glass has a built in lens that changes the apparent focal length.

Although it is close to your eye, thanks to some ingenious design in the prism you see the image as actually being further away (about 1.5m away). This stops the eye from trying to refocus every time you want to use the device.

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