Dr. Raymond Soneira sent a long and detailed response to this article shortly after it was published. While parts of it recapitulate his response to the Discover article cited above, he also includes some new information and argument that warrant this update:
My analysis and comments on the Retina Display were widely distorted and transformed into an attack on Apple and Steve Jobs — they were not. I simply did a quantitative analysis of what was said in the context of my campaign to eliminate (or more realistically reduce) exaggeration in display specs. Apple's claim falls under glorious wording rather than numerical spec abuse — and even with quantitative analysis it's minor compared to what other manufacturers are saying. I sent Steve Jobs an Email explaining that and got a reply from him.In his email to the The Reg, Soneira reiterates that his disagreement is with Apple's use of the term "Retina Display" and Steve Jobs' statement that the iPhone 4's display has a resolution that exceeds "the limit of the human retina to differentiate the pixels."
I used the accepted value for the visual acuity of the Retina (see below) and found that the iPhone was more than a factor of 2 short on pixels to be a Retina Display. The iPhone 4 would need to have 1.3 megapixels instead of 0.6 megapixels to be a true Retina Display at 12 inches. At 10 inches it would need even more — 1.9 megapixels — a factor of 3 short.There have been some comments that my analysis is for perfect vision. Jobs' statement is for the *Retina* not the *Eye* with 20/20 or other vision. For 20/20 vision the accepted value is to resolve two lines that are separated by 1.0 arc minute. In that case a 20/20 vision display needs a resolution of 286 dpi or higher at 12 inches and 344 dpi at 10 inches. The iPhone 4 has 326 dpi, so at 12 inches it is a 20/20 Vision Display but not a Retina Display.Soneira sums up his argument by saying: "The iPhone 4 is a fabulous display, it's just not a Retina Display — but it's good enough for 20/20 vision when held at 12 inches or more from the eye."
Using the information above, and based on the size of the iPhone 4's screen, 3.5", and its resolution 960X640 = 614,400 pixels), the pixel density would indicate this new display on the HTC at the same pixel density would be 3.154 times more display area (1794X1080 = 1,937,520 pixels), We're talking small tablet size here based on my math (1937520/614400 = 3.154 times the display area).