“Dr. Raymond Soneira runs DisplayMate Technologies,” Jason Cross reports for PC World. “This morning, Dr. Soneira shot me an interesting email regarding the so-called ‘Retina Display’ of the iPhone 4. To clarify: a retina display is one whose resolution meets or exceeds the maximum resolution the human retina is capable of resolving, assuming perfect vision.”
Dr. Soniera’s email, in full and unedited, is as follows:
The iPhone 4 has an outstanding display… and I’m glad that Apple resisted the emotional rush to OLEDs because they still need lots of improvement before they will be ready to compete with the highly refined IPS LCDs. The iPhone 4 display should be comparable to the outstanding IPS LCD in the Motorola Droid, which I tested and compared to the Nexus One OLED, which was trounced by the Droid.
Steve Jobs claimed that the iPhone 4 has a resolution higher than the retina – that’s not right:
1. The resolution of the retina is in angular measure – it’s 50 Cycles Per Degree. A cycle is a line pair, which is two pixels, so the angular resolution of the eye is 0.6 arc minutes per pixel.
2. So if you hold an iPhone at the typical 12 inches from your eyes, that works out to 477 pixels per inch. At 8 inches it’s 716 ppi. You have to hold it out 18 inches before it falls to 318 ppi.
So the iPhone has significantly lower resolution than the retina. It actually needs a resolution significantly higher than the retina in order to deliver an image that appears perfect to the retina.
It’s a great display, most likely the best mobile display in production (and I can’t wait to test it) but this is another example of spec exaggeration.
Full article here.
MacDailyNews Take: In his WWDC 2010 keynote address, Apple CEO Steve Jobs explicitly stated (beginning at 36:35), “The Retina display has 326 pixels per inch. There’s never been a display like this on a phone. People haven’t even dreamed of a display like this on a phone. But, it’s more than that. It turns out that there’s a magic number, right around 300 pixels per inch that when you hold something around 10 or 12 inches away from your eyes is the limit of the human retina to differentiate the pixels. And so they’re so close together when you get at this 300 pixels per inch threshold that, all of a sudden, things begin to look like continuous, continuous curves. Like text looks like when you’ve seen it in a fine printed book. Unlike you’ve ever seen on an electronic screen before. And, at 326 pixels per inch, we are comfortably over that limit.”
If you want to argue with that, you need to get a life.
According to Wikipedia, in the term “20/20 vision,” the numerator refers to the distance in feet between the subject and the chart. The denominator is the distance at which the lines that make up those letters would be separated by a visual angle of 1 arc minute, which for the lowest line that is read by an eye with no refractive error (or the errors corrected) is usually 20 feet. The metric equivalent is 6/6 vision where the distance is 6 meters. This means that at 20 feet or 6 meters, a typical human eye, able to separate 1 arc minute, can resolve lines with a spacing of about 1.75mm. At 12 inches, the normal visual acuity of the human eye is 0.00349 inch. We’re not sure where the good doc is getting “0.6 arc minutes per pixel” unless he’s using Superman as his baseline.
Dr. Soniera should seek better ways to garner free publicity for DisplayMate Technologies.
Direct link to video via YouTube here.