There has been some debate on the internet about the iPhone 4 Retina Display, and whether or not Steve Jobs has been exaggerating again.
So we thought we’d do our best to clear this up for you.
Steve Jobs had this to say about the iPhone 4’s LCD display resolution during his WWDC keynote :
It turns out there’s a magic number right around 300 pixels per inch, that when you hold something around to 10 to 12 inches away from your eyes, is the limit of the human retina to differentiate the pixels.
In other words, text will look like printed characters in a book on your new iPhone 4’s screen.
Some blogs, spurred on by experts in the field of displays, have taken exception to Steve Jobs’ claim. Raymond Soneira, armed with a theoretical physics Ph.D. from Princeton University has gone away and done some maths based on angular resolution and stuff, and come up with a figure of 477 pixels per inch as being the theoretical density actually required for pixels to merge into each other at 12 inches from the human eye on an LCD panel.
This made me curious. How could Steve Jobs be so far out, and not expect to get called on it. The Retina Display only has 326 pixels per inch after all. That’s over 150 less than Soneira says is required for the capability that Apple claims the Retina Display has.
Now I don’t have a Ph.D., and can’t argue directly with Raymond’s figures, but I was able to find another person’s opinion, who I have reason to respect. He’s one of the scientists who works on the optics of the Hubble Telescope.
It’s certainly worth reading Phil Plait’s full explanation, and I have included a link at the bottom of this article if you want to go ahead and do just that. But for those that just want his final conclusion I will simplify it here.
The iPhone’s pixels at 12 inches from your face are 0.0031 inches across.
With absolutely perfect vision, you should be able to discern things as small as 0.0021 inches across. i.e. You could ace a fighter pilot’s eye-test, not just pass. And your eyesight would rival that of a bird of prey.
Well it doesn’t take a maths expert to see that a fighter pilot may well be able to see the pixels on an iPhone 4’s Retina Display.
But we are overlooking something quite obvious here. The majority of humans do not have absolutely perfect eye sight. In fact a surprisingly high number of them don’t even have 20/20 vision. Even with 20/20 vision (eyesight that does not require you to wear glasses) you actually can’t resolve anything smaller than 0.0035 inches.
Again, it doesn’t take a maths expert to see that people with 20/20 vision and below will not be able to discern individual pixels on an iPhone 4’s LCD.
Phil’s conclusion is as follows :
Aha! This means that to a more average eye, pixels smaller than this are unresolved. Since the iPhone’s pixels are 0.0031 inches on a side, it works! Jobs is actually correct.
In a slightly less scientific test I took a graph I have from when I chose my HDTV for my sitting room.
Now what this graph does is let you know how far away your HDTV can be from your sofa before you won’t be able to tell the difference between 480p, 720p, 1080p, or even 1440p. By extending the graph lines from the area that said I wouldn’t be able to see the difference between any display resolution. i.e. A normal TV picture would look the same to me as a 1440p HDTV, I was able to come up with a rough figure of 320 pixels per inch for an HDTV 12 inches from my nose, and the same size as an iPhone!
I can only assume that HDTV manufacturers want to sell HDTV TVs, and to sell the most expensive model possible, so have more than likely fudged the figures in their favour slightly. So if anything they would be trying to get me to buy a higher resolution HDTV than I really need. Even with their graphs they seem to confirm what Apple have been saying too.
In short, unless you have the eyesight of a bird of prey, rest assured that the Retina Display is going to look awesome.
So, who do you believe? A Hubble Telescope Engineer, Steve Jobs, or a pernickety guy with a Ph.D? Let us know your thoughts in the comments.
Phil Plait: [Full Explanation] ]]> https://touchreviews.net/iphone-4-retina-display-fact-fiction/feed/ 0
The iPhone 4 is certainly much more than I expected it to be. I was hopeful of an even higher resolution screen than we got. But other than that I was simply anticipating what most other people were expecting. Smaller, faster, neater, video calls, and a stills camera with flash.
That is not to say that video calls, or a 5MP camera – with LED flash – are not good things. But they were kind of a given, and to be expected on any current generation smart phone. So getting excited about those features takes a little more effort. That’s all.
So where did the iPhone 4 really “Wow” me?
Well a fairly full featured version of iMovie available for the iPhone in the App Store at launch, and 720p recording was a pleasant surprise. Plus it’s Apple, so we know that it will “just work” beautifully too. So when these features are simply demoed on stage we can relax safe in the knowledge that the final product we get later this month will do all that it is advertised as doing. But even then, Nokia had video editing on their N series phones a while back I seem to remember.
I am also glad that Apple refrained from calling the iPhone 4, “iPhone HD”. It’s not HD. The screen resolution is not high enough, even if the phone itself records in half-way HD. And HD would have caused a lot of confusion with iPad app names – as I have often suggested to deaf ears. I have to admit to a little bit of smug satisfaction watching most of my fellow industry pundits call it that over the last few months, whereas I refrained, except where chastised by my editor for “SEO reasons”. Whatever that means!?! 
But I still haven’t said what really blew me away about the iPhone 4 yet, have I? No! Sorry! Ok.. In order of no particular importance…
The iPhone 4’s screen construction.
It was common knowledge a fair while before launch that the iPhone 4 would feature a more traditional LCD panel, rather than an OLED one. This was a sensible choice from Apple, as OLED has been shown on various Android devices to deliver fairly lacklustre results so far. OLED has certainly not been shown yet, in smartphone form, to be able to deliver the crispness or quality we expect of Apple gear.
What Apple have also done is incorporate a hybrid of IPS and FFS technologies into the 960×640 LCD panel in the iPhone 4. Those technologies are specifically suited to a versatile range of viewing angles, and clarity of view specifically for text heavy applications. Think eBooks, PDFs and web pages. Games, and pictures always look good with a bright, well balanced display – which high quality LCDs produce better than OLED currently also. So Apple worked on what it was important for them to work on. Which is what makes them market leaders after all.
But that’s still not what is really cool about the screen. Their choices so far are what we’d expect from Apple. In other words, the best possible implementation of stable and current technology, rather than new “bleeding-edge” technology just for the sake of it.
What is really cool though is that Apple have reengineered how they make their screens. In doing so they have made it so that there is literally no space between the touch layer and the LCD itself.
Engineering. This is where Apple consistently outshine other OEMs. Their new method of making their composite touch / LCD panels, coupled with the beautiful glass front panel of the iPhone 4 puts our fingers literally on top of the LCD itself. When you look at the new iPhone the screen literally looks like a bright shiny sticker stuck on the outside of the iPhone. It is truly incredible. When you see one in the flesh, that alone will make you want one. I guarantee it. And my name is not Steve Jobs!
The Stainless Steel Case
Stainless Steel has several properties that the Aluminium cases that Apple has favoured to date, do not. It conducts radio waves very well, and it has a heft to it that feels more solid and satisfying. It’s also far stronger.
By combining a practical quality of Stainless Steel, with an aesthetic quality they have produced both a high quality / high performance arial framework for all the various radio signals the iPhone 4 produces, coupled with a healthy feeling heft, and strong construction to the entire device. The iPhone 4 is solid, and receives and transmits strong signals.
Apple have gone one step further still by making the edges of the device square, rather then rounded like previous iPhones, so that it genuinely feels more like a camera when you turn it on its side to use it as one. Again, when you get your hands on one in an Apple Store, or when you steal your friend’s iPhone 4 for a few precious moments you’ll see what I mean.
iOS
This is not an obvious feature of the iPhone 4. But what Apple have done is start to refine their iPhone / iPod Touch and iPad OS into one Operating System : iOS.
Part of the reason for this is to bring the various screen sizes that we will inevitably have more of in future, and have now on current devices, under the control of the OS.
For games it is not such an issue. Games makers can just scale graphics to fit the screen, and choose to have, or not have, various levels of detail for textures and other images. But for applications, which is after all what Apple is more interested in, and has to put more work into supporting visually, different screen resolutions is an important issue. And potentially a problem.
Imagine if the 200,000+ apps in the App Store today all had to be re-written for the new iPhone? Developers would not be happy. Apple has addressed this issue with various technologies in iOS (previously iPhone OS 4.0), and will continue to do so moving forward. Currently it is in an early form, but has already improved on the crude 2X feature of iPhone OS 3.2, which is currently found on the iPad for using existing iPhone apps.
Whilst not completely realising their final goal Apple have, in my opinion, taken an important first step towards Resolution Independence in iOS. The best is yet to come. But this is a solid foundation to build from.
iPhone 4, and iOS is where it starts to come together.
The Gyroscope
Steve actually demonstrated the iPhone 4’s gyroscope with a game of Jenga. I found that quite amusing. Apple have not been great at promoting games as a medium in the past. Even with their new found romance with games on the iPod Touch, iPhone and iPad they are still not taken seriously on Apple’s desktop lineup.
Ironically though I don’t think the gyro will find its greatest success in games. There are still a lot of iPods and iPhones, and brand new iPads out there that don’t have this feature. And for a while, at least, games writers will have to ensure their games work with the older Accelerometers found in earlier devices.
Some forward thinking developers will have a gyroscope option in their games. But important aspects of game play won’t be able to rely on the increase in accuracy and freedom of movement that the new component undoubtably brings… for the immediate future anyway. Otherwise the game will suffer on older devices, and the core market at the moment.
Where I think the gyroscope will be amazing is in Augmented Reality applications. At the moment looking around and using the camera in an existing iPhone to view our environment and overlay information and advertising on the world around us is a popular gimmick in “AR” apps. But the view is clunky and a bit jittery in most mobile devices (including current iPhones) because of the lack of precision that accelerometers offer. With a gyroscope on the new iPhone 4 Augmented Reality is set to go mainstream. This will be helped by the increased speed of the A4 processor, and the increased accuracy of the gyroscope.
Expect a lot of iAd enabled gyroscope using Augmented Reality apps to hit the App Store very soon.
As a little bit of background for you. The last gyroscope I programmed for was a component that was used in guided missiles originally. Our use for it was entirely different. But that is the kind of precision, and freedom of movement that gyroscope technology is derived from. Think about that for a minute. Your iPhone 4 will be distantly related to a guided missile! Cool eh!
Finally, a quick note about the 5MP camera in the iPhone 4
Apple could have played the numbers game here. They could have gone for 8 or 16 MP unit. And some Android owners may well quote the 8MP pixel camera in the new HTC EVO 4G to backup that line of thinking. But in reality until you make your lenses and your CCD (the device that receives the image inside your phone) bigger and of better quality there is no point. With the current form factor of all smart phones, their lenses and CCDs, more Megapixels just equate to bigger pictures, with more noise, which take up more space on your Flash Memory. Pictures which overall are of the same quality by and large – just noisier.
5 – 6 Megapixels is the optimum size for consumer cameras of the kind of lens dimension we are seeing on these phones. Any more is simply there for bragging rights for the OEM, and offers no functional advantage. Period.
What Apple have done, again, is focus on making the entire package better. Apple’s CCD in the iPhone 4 is designed to get more photons, more accurately, with less noise into your iPhone’s storage. In the iPhone 4’s case they do it by using Backside illumination :
Wikipedia explains Backside illumination this way :
In a device with backside illumination, the silicon light sensor for each pixel is on the “back” side of the silicon wafer, opposite the transistors and metal wiring layers. This increases the efficiency of the sensor as compared to the traditional (“frontside illumination”) technology, in which some of the light is scattered by the circuit layers on the front side of the wafer before it can reach the image sensor.
Here is a good example which illuminates the point I am making about megapixel count perfectly :
Joe Holmes’ limited-edition 13 x 19″ prints of his American Museum of Natural History series sell at Manhattan’s Jen Bekman Gallery for $650 each. They’re made on a 6MP D70.
No the iPhone 4’s lens is certainly not up to the standard of one found in a Nikon D70. Not is the one found in the HTC EVO 4G, or any other smart phone for that matter. But they have CCDs of roughly the same quality. The iPhone 4 has one which is better suited than all of them to low light conditions, and getting the best performance possible out of its surrounding hardware.
So there you have it. Those are the things about the iPhone 4 that excite me! What is your favourite feature of the new iPhone 4? Let us know in the comments.
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