7 ms·

IPhone 4’s ‘Retina’ Display Claims Are False Marketing

47 points by yumraj 16y ago

amayne 16y ago
Wired's headline is false journalism... Phil Plait, a Hubble astronomer politely debunks the Wired article here: http://blogs.discovermagazine.com/badastronomy/2010/06/10/resolving-the-iphone-resolution/ http://blogs.discovermagazine.com/badastronomy/2010/06/10/re...
- scott_s 16y ago
  Better ending: "... resolved the issue."
- amirmc 16y ago
  Phil didn't point out that pupil dilation also is a factor (presumably for the sake of simplicity). You might be able to resolve two points in one lighting condition but not in another.
- FlorinAndrei 16y ago
  1 arcmin for the human eye's resolving power was the value I always used. I was surprised to learn about this whole "50 cycles" thing.
teilo 16y ago
Near the end of the article: "Sharp Quattron’s fourth primary color is yellow, and there is nothing for it to do because yellow is already reproduced with mixtures of the red and green primaries, he said." This 20-year display "expert" has never heard of hi-fidelity color? Inexcusable. It is accurate to say that yellow is not a primary color of light, so it is true enough that no one should refer to the yellow pixels as a "fourth" primary color. However, it is completely false to say that "there is nothing for it [the yellow pixels] to do". The yellow pixels are used to extend the gamut of the device to cover portions of the visible spectrum that the primary LEDs, in combination, cannot. We do this all the time with Hi-Fi printers. We add RGB or Orange, Green, and Violet to the traditional CMYK primaries to expand the gamut of the device far beyond what traditional process color can accomplish.
- evgen 16y ago
  > The yellow pixels are used to extend the gamut of the device to cover portions of the visible spectrum that the primary LEDs, in combination, cannot. What color in the visible spectrum cannot be expressed as a combination of red, green, or blue? Octarine perhaps? Adding additional colors only helps if your pixels are large and putting a red and a blue dot next to each other when aiming for purple ends up just looking like two dots of different colors instead of a combined dot.
  - teilo 16y ago
    Your sarcasm does not become you. Neither does your ignorance. If you actually worked in the field of color management, like I do, you would know that, as with subtractive pigments, so with LEDs: There is no such thing as a pure primary in the real world. It is impossible to create an LED or a color of ink that is mathematically perfect pure Red, Green, or Blue. Because of this it is impossible for an RGB-only display to display all colors that are visible to the human eye. (Let's exclude UV-florescence from the equation for the sake of simplicity). RGB displays use color correction curves and various profiling tricks to correct for the difference between the pure primaries and the actual light being output by the LEDs. Yellow LEDs can extend the color range of an RGB display into areas of the gamut that the display could not otherwise "hit". The same could be said for (presumably theoretical) Cyan or Magenta LEDs.
    - ugh 16y ago
      How does the technology used to capture the video factor into that? I would assume that with capturing only RGB you already limited the color space – the information is lost – and you cannot extend it, no matter what you try. I know that, when printing, additional colors can help because the RGB space doesn’t map exactly to the CMYK space. There are RGB colors you just cannot get with CMYK. Are the RGB(capture) and RGB(display) color spaces so different that additional colors can help? I would assume they would have to be, wouldn’t they?
      - teilo 16y ago
someone_here 16y ago
Is this important?
- gte910h 16y ago
  It will likely cause purchases of the device that would not otherwise happen. In the US, your advertising is required to be truthful, or at worst, vague claims. Those images are neither. Now I honestly believe Jobs misunderstood the science, as he's a suit, not an eye doctor/etc, but they shouldn't repeat that anymore now that they've been corrected until they can show their claim is true.
zyb09 16y ago
Well it's a 960x640 display, which is pretty cool, no? Don't know why they've come up with this whole "retina" BS, but that's just Apple I guess.
latch 16y ago
A CEO "pushed it a little too far" ? SHOCKED!
tomerico 16y ago
the eye actually has an angular resolution of 50 cycles per degree. My calculations: degrees in one inch - arcsin(1/12) = 4.78 Pixels in eye for one inch, 12" away - 4.78 * 50 = 240 Same calculations for 10" arcsin(1/10)*5 = 287 I think something is wrong with the numbers in the article
- gjm11 16y ago
  50 cycles per degree is not the same as 50 pixels per degree. If your eye can resolve 50 cycles per degree, that means it can tell the difference between a uniform grey and something that alternates between black and white 50 times per degree. To display such a pattern, you'd need 100 pixels per degree (black, white, black, white, ..., with 50 pairs).
  - abeppu 16y ago
    I don't think it's entirely clear from the article what 'cycle' should mean in this context. But 1/50 of a degree matches relatively closely to the traditional Snellen (as in the guy who made the eye charts) definition of normal vision (20/20 or 6/6 in metric countries http://en.wikipedia.org/wiki/Visual_acuity#Normal_vision http://en.wikipedia.org/wiki/Visual_acuity#Normal_vision) as being able to discern letters whose features were 1 minute of arc(e.g. 1/60 of a degree). At 12 inches, the angle subtended by a pixel (which is, I think, the corresponding minimum feature size) is arcsine( (1 in /326)/12 in) is 0.88 minutes (that is, less than the 1 minute Snellen definition of normal vision, which is in turn smaller than the 1/50 definition that this guy gives). So I think Soneira guy is off base. But I think the much bigger problem is that both Soneira and the 1 minute definition are talking about the acuity of a 'normal' person, and seem to be largely ignoring the issue of a significant variation in the population. My question is, for what portion of the population does this display exceed the limits of their visual acuity?
    - gjm11 16y ago
      The definition in that Wikipedia article says that 20/20 vision means being able to resolve two points separated by one arc-minute. Again, on the output side that would mean being able to display two points at that separation with something contrasting in between. On the other hand, elsewhere Wikipedia says that it means being able to distinguish Snellen optotypes whose total size is one arc-minute. On the face of it, that implies more resolution than two pixels per arc-minute. (Hand-wavily, maybe it's about the same: if you can resolve 2x2 pixels in a square of side 1 arcminute, then for high-contrast Snellen-type images that maybe suggests that you ought to be able to distinguish about 2^(2x2) = 16 different such images, and a Snellen chart actually uses 10 or 12 different optotypes, depending on whether it's one of Snellen's original ones or a modern variant. That's pretty close to 16.) Phil Plait's blog entry that someone else linked to talks about the difference between "normal" and "ideal", and concludes that an average person looking at a new iPhone at 1' distance will indeed not be able to resolve the pixels (though not by much).
deleted 16y ago
[deleted]
pjdavis 16y ago
I think "marketing puffery" is an apt description for this article.
- Tamerlin 16y ago
  It's not like Apple is a stranger to marketing puffery... remember the SPEC CPU claims for the G5?
URSpider94 16y ago
This article is a mess. First of all, iPhone 4's 300 "pixels" per inch actually comprise three color sub-pixels each. Most display drivers today can use the color sub-pixels to carry spatial as well as color information, so that would bump the performance of this display comfortably over the detection threshold of the human eye. Second, the throw-away comment that "magazines are printed at 300 dots per inch" is incorrect and mis-leading. Dots are not the same as pixels, a printed dot is either "on" or "off". A magazine printed at 300 dpi has a substantially lower actual resolution than a 300 pixel-per-inch display that can render 18-24 bits of color at each pixel. Finally, as others have mentioned, the slamming of Sharp's Quattron technology is wrong-headed. Adding a yellow pixel can significantly increase the color gamut of an LCD display, since in many cases the color resists used to make the RGB color filters do a particularly poor job of producing yellows.

47 points by yumraj 16y ago

Wired's headline is false journalism... Phil Plait, a Hubble astronomer politely debunks the Wired article here: http://blogs.discovermagazine.com/badastronomy/2010/06/10/resolving-the-iphone-resolution/ http://blogs.discovermagazine.com/badastronomy/2010/06/10/re...

scott_s 16y ago
Better ending: "... resolved the issue."
amirmc 16y ago
Phil didn't point out that pupil dilation also is a factor (presumably for the sake of simplicity). You might be able to resolve two points in one lighting condition but not in another.
FlorinAndrei 16y ago
1 arcmin for the human eye's resolving power was the value I always used. I was surprised to learn about this whole "50 cycles" thing.

teilo 16y ago

Near the end of the article: "Sharp Quattron’s fourth primary color is yellow, and there is nothing for it to do because yellow is already reproduced with mixtures of the red and green primaries, he said." This 20-year display "expert" has never heard of hi-fidelity color? Inexcusable. It is accurate to say that yellow is not a primary color of light, so it is true enough that no one should refer to the yellow pixels as a "fourth" primary color. However, it is completely false to say that "there is nothing for it [the yellow pixels] to do". The yellow pixels are used to extend the gamut of the device to cover portions of the visible spectrum that the primary LEDs, in combination, cannot. We do this all the time with Hi-Fi printers. We add RGB or Orange, Green, and Violet to the traditional CMYK primaries to expand the gamut of the device far beyond what traditional process color can accomplish.

evgen 16y ago
> The yellow pixels are used to extend the gamut of the device to cover portions of the visible spectrum that the primary LEDs, in combination, cannot. What color in the visible spectrum cannot be expressed as a combination of red, green, or blue? Octarine perhaps? Adding additional colors only helps if your pixels are large and putting a red and a blue dot next to each other when aiming for purple ends up just looking like two dots of different colors instead of a combined dot.
- teilo 16y ago
  Your sarcasm does not become you. Neither does your ignorance. If you actually worked in the field of color management, like I do, you would know that, as with subtractive pigments, so with LEDs: There is no such thing as a pure primary in the real world. It is impossible to create an LED or a color of ink that is mathematically perfect pure Red, Green, or Blue. Because of this it is impossible for an RGB-only display to display all colors that are visible to the human eye. (Let's exclude UV-florescence from the equation for the sake of simplicity). RGB displays use color correction curves and various profiling tricks to correct for the difference between the pure primaries and the actual light being output by the LEDs. Yellow LEDs can extend the color range of an RGB display into areas of the gamut that the display could not otherwise "hit". The same could be said for (presumably theoretical) Cyan or Magenta LEDs.
  - ugh 16y ago
    How does the technology used to capture the video factor into that? I would assume that with capturing only RGB you already limited the color space – the information is lost – and you cannot extend it, no matter what you try. I know that, when printing, additional colors can help because the RGB space doesn’t map exactly to the CMYK space. There are RGB colors you just cannot get with CMYK. Are the RGB(capture) and RGB(display) color spaces so different that additional colors can help? I would assume they would have to be, wouldn’t they?
    - teilo 16y ago

someone_here 16y ago

Is this important?

gte910h 16y ago
It will likely cause purchases of the device that would not otherwise happen. In the US, your advertising is required to be truthful, or at worst, vague claims. Those images are neither. Now I honestly believe Jobs misunderstood the science, as he's a suit, not an eye doctor/etc, but they shouldn't repeat that anymore now that they've been corrected until they can show their claim is true.

zyb09 16y ago

Well it's a 960x640 display, which is pretty cool, no? Don't know why they've come up with this whole "retina" BS, but that's just Apple I guess.

latch 16y ago

A CEO "pushed it a little too far" ? SHOCKED!

tomerico 16y ago

the eye actually has an angular resolution of 50 cycles per degree. My calculations: degrees in one inch - arcsin(1/12) = 4.78 Pixels in eye for one inch, 12" away - 4.78 * 50 = 240 Same calculations for 10" arcsin(1/10)*5 = 287 I think something is wrong with the numbers in the article

gjm11 16y ago
50 cycles per degree is not the same as 50 pixels per degree. If your eye can resolve 50 cycles per degree, that means it can tell the difference between a uniform grey and something that alternates between black and white 50 times per degree. To display such a pattern, you'd need 100 pixels per degree (black, white, black, white, ..., with 50 pairs).
- abeppu 16y ago
  I don't think it's entirely clear from the article what 'cycle' should mean in this context. But 1/50 of a degree matches relatively closely to the traditional Snellen (as in the guy who made the eye charts) definition of normal vision (20/20 or 6/6 in metric countries http://en.wikipedia.org/wiki/Visual_acuity#Normal_vision http://en.wikipedia.org/wiki/Visual_acuity#Normal_vision) as being able to discern letters whose features were 1 minute of arc(e.g. 1/60 of a degree). At 12 inches, the angle subtended by a pixel (which is, I think, the corresponding minimum feature size) is arcsine( (1 in /326)/12 in) is 0.88 minutes (that is, less than the 1 minute Snellen definition of normal vision, which is in turn smaller than the 1/50 definition that this guy gives). So I think Soneira guy is off base. But I think the much bigger problem is that both Soneira and the 1 minute definition are talking about the acuity of a 'normal' person, and seem to be largely ignoring the issue of a significant variation in the population. My question is, for what portion of the population does this display exceed the limits of their visual acuity?
  - gjm11 16y ago
    The definition in that Wikipedia article says that 20/20 vision means being able to resolve two points separated by one arc-minute. Again, on the output side that would mean being able to display two points at that separation with something contrasting in between. On the other hand, elsewhere Wikipedia says that it means being able to distinguish Snellen optotypes whose total size is one arc-minute. On the face of it, that implies more resolution than two pixels per arc-minute. (Hand-wavily, maybe it's about the same: if you can resolve 2x2 pixels in a square of side 1 arcminute, then for high-contrast Snellen-type images that maybe suggests that you ought to be able to distinguish about 2^(2x2) = 16 different such images, and a Snellen chart actually uses 10 or 12 different optotypes, depending on whether it's one of Snellen's original ones or a modern variant. That's pretty close to 16.) Phil Plait's blog entry that someone else linked to talks about the difference between "normal" and "ideal", and concludes that an average person looking at a new iPhone at 1' distance will indeed not be able to resolve the pixels (though not by much).

deleted 16y ago

[deleted]

pjdavis 16y ago

I think "marketing puffery" is an apt description for this article.

Tamerlin 16y ago
It's not like Apple is a stranger to marketing puffery... remember the SPEC CPU claims for the G5?

URSpider94 16y ago

This article is a mess. First of all, iPhone 4's 300 "pixels" per inch actually comprise three color sub-pixels each. Most display drivers today can use the color sub-pixels to carry spatial as well as color information, so that would bump the performance of this display comfortably over the detection threshold of the human eye. Second, the throw-away comment that "magazines are printed at 300 dots per inch" is incorrect and mis-leading. Dots are not the same as pixels, a printed dot is either "on" or "off". A magazine printed at 300 dpi has a substantially lower actual resolution than a 300 pixel-per-inch display that can render 18-24 bits of color at each pixel. Finally, as others have mentioned, the slamming of Sharp's Quattron technology is wrong-headed. Adding a yellow pixel can significantly increase the color gamut of an LCD display, since in many cases the color resists used to make the RGB color filters do a particularly poor job of producing yellows.