NOT!
According to
Jonesblog written by Dr Bryan Jones (Retinal Neuroscientist):
Essentially, this is a claim of visual acuity which is the ability of the visual system to resolve fine detail. There are an awful lot of considerations to take into account when making such a claim such as contrast, distance, the resolution of the display and some metric of pixel size which gives you an estimate of visual resolution on the retina. Claims of contrast ratios are notoriously flexible in a number of displays and will be influenced by a number of optical factors as well as the content being viewed and the black and color levels of the pixels as well as overall luminance. Apple claims an 800:1 pixel ratio and Ill take them at their word on that and focus on the claims of resolution here.
A normal human eye is considered to have standard visual acuity or 20/20 vision. This means that a 20/20 eye can discriminate two lines or two pixels separated by 1 arcminute (1/60 degree).
The ability of an optical system to resolve fine detail requires minute spacing of optical detectors. In the retina, there detectors are the photoreceptors. Objects we look at at projected through the cornea and lens and imaged on the back of the eye on a plane that ideally lines up with the retinal photoreceptors.
Theoretically the limit of retinal resolution, say the ability to distinguish patterns of alternating black and white lines is approximately 120pixels/degree in an optimal, healthy eye with no optical abnormalities. Again, this corresponds to one minute of arc or 0.000291 radians (π/(60*180)). If one assumes that the nominal focal length of the eye is approximately 16mm, an optimal distance from the eye for viewing detail might be around 12 inches away from the eye which is reasonable to assume for someone viewing detail on their iPhone.
Dr. Soneiras claims are based upon a retinal calculation of .5 arcminutes which to my reading of the literature is too low. According to a relatively recent, but authoritative study of photoreceptor density in the human retina (Curcio, C.A., K.R. Sloan, R.E. Kalina and A.E. Hendrickson 1990 Human photoreceptor topography. J. Comp. Neurol. 292:497-523.), peak cone density in the human averages 199,000 cones/mm2 with a range of 100,000 to 324,000. Dr. Curcio et. al. calculated 77 cycles/degree or .78 arcminutes/cycle of *retinal* resolution. However, this does not take into account the optics of the system which degrade image quality somewhat giving a commonly accepted resolution of 1 arcminute/cycle. So, if a normal human eye can discriminate two points separated by 1 arcminute/cycle at a distance of a foot, we should be able to discriminate two points 89 micrometers apart which would work out to about 287 pixels per inch. Since the iPhone 4G display is comfortably higher than that measure at 326 pixels per inch, Id find Apples claims stand up to what the human eye can perceive.
According to Adrian Covert of
Gizmodo:
This same line of thinking manifested itself when contrast ratio became a spec for Plasma and LCD displays (OMG ONE ZILLION TO ONE CONTRAST RATIO) cant see it, doesnt matter and is now resurfacing as companies enter the pixel density arms race. Increases in pixel density are going from impressive technical feats to masturbatory experiments for the sake of marketing strategy.
So what do we make of HTC managing to pack a 1920×1080 display in a 5-inch screen? When it comes to tangible user benefits, not much. According to those who toil away in research labs, the human eye can not discern granular detail when it is higher than 300 PPI. Hence Apples 326 PPI display in the iPhone 4 back in 2010. Yes, some notably Dr Raymond Soneira of DisplayMate have argued that no display will be perfectly retina until it has a density of 477 PPI. But others, like University of Utah professor Bryan Jones, dispute the basis of Soneiras reasoning, arguing that from a foot away, displays will actually appear retina when greater than 287 PPI. But even Soneira acknowledged that the retina effect kicks in when a 300 PPI display is held 18 inches away. You know. Where you hold your phone.
Does increased smartphone resolution help for watching high-def movies? Not really. To really reap the benefit of 1080p video, you need no smaller than a 40-inch display (and ideally one above 50-inches) to notice anything awesome while sitting at a comfortable distance. In fact, to theoretically reap any benefits of 1080p video on your phone, youd need to be holding it 6-8 inches from your face. No one holds their phone 6-8 inches from their face.