Apple's iPhone 4: Thoroughly Reviewed
by Brian Klug & Anand Lal Shimpi on June 30, 2010 4:06 AM EST- Posted in
- Smartphones
- Apple
- iPhone 4
- Gadgets
- Mobile
Screen - Retina Display
Right out of the box, the iPhone 4's new 326 PPI, 960x640, 3.5" display is arguably the single most striking change the new iPhone brings. In a word, it's dazzling. Text and high res images look amazingly sharp on the iPhone 4’s retina display. It’s an improvement over the 800 x 480 AMOLED screens that have been shipping on most Android phones. But if you’re comparing it to an iPhone 3GS the difference is huge.
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iPhone 3GS
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iPhone 4
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Text on the Google Nexus One
Text on the iPhone 4
The dot pitch is truly remarkable, so much so that Apple makes the claim that their display outresolves the human eye; its advertised ability to do so has earned it a new Apple tradename, "retina display."
Text on the HTC EVO 4
Text on the iPhone 4
AnandTech Logo on the EVO 4G
AnandTech Logo on the iPhone 4
Immediately after hearing Apple's claim that the Retina Display outresolves the human eye, I snapped into optics mode and crunched the numbers, and tweeted that the results were valid.
In the days that followed, there was considerable debate about the validity of Apple's claims. However, nearly all of the debate really just hinged on a debate over angular resolution of the human eye, and a little more over viewing distance. They're both entirely conventions.
As you've probably discovered by now, the human eye resolution can really only be characterized in angular subtense. Hold something closer to your eye, and you can see smaller features better (in theory), move it further away, and you can't make out small spatial details. The minimum angle visible with the human eye is the angle at which features (for the most common definition, a black and white square wave) stop being visible, and are indistinguishable from each other.
Most measures of visual acuity test with this implicitly - the Snellen eye chart's use of the capital "E" is literally a perfect example, which has given rise to a "tumbling E" eye chart. At twenty feet, the capital E subtends 5 minutes of arc, and conveniently has five half cycles of white to black (from top to bottom). So 20/20 implicitly implies an angular resolution of 1 arcminute (1/60 degrees).
As an Optical Sciences and Engineering undergrad, I've had 1 arcminute drilled into my head more times than I can count as being the "normal" angular resolution of the human eye system. In practice, this is 20/20 vision, which is "normal," yet not perhaps the absolute maximum for human perfection. We can play games of course and argue that a small subset of the population has better than normal uncorrected vision, and thus an angular resolution of below 1 arcminute. I have above average uncorrected vision, which I've measured to be 20/15 on average, giving an angular resolution of approximately 0.75 arcminutes. Of course, the definitions stem from the spacing of cones in the fovea, the highest resolution part of the retina.
The other informational quantity needed to test the Retina Display claims is viewing distance. Again, there's a commonly agreed upon convention - standard viewing distance is considered to be 1 foot. This is another drilled into my brain number tossed around for comfortable viewing and reading. In practice, you can focus on objects much closer to your eye - this is called the near point and is often given as 10 inches, though as you get closer you increase strain aren't likely to keep it here.
Maybe not exactly the limit, but close enough.
Given the two most common standards tossed around, 1 arcminute and 12 inches, do the math out and you'll arrive at around 286 pixels per inch as the limit for eye resolving power, comfortably below the 326 on the Retina Display. Move to 0.75 arcminutes at 12 inches, and it's 382 pixels per inch, higher than the Retina Display. Honestly, I can't see the pixels at 12 inches.
Of course, the real story is even more complicated. Remember how the definition comes with the implicit assumption that we're dealing with a square wave pattern from white to black? That's a factor too - the contrast of the two pixels. Lower the contrast, and the eye's ability to pick out features decreases even more. So far, everything we've talked about has been first order, and without aberrations. Toss in spherical and astigmatism, two aberrations common to the eye system, and eye performance drops way more.
The human eye system is actually pretty poor, and shockingly easy to outresolve. In fact, if you saw the image your eye forms on your retina, you'd likely be appalled; it's your brain that makes the system usable. But at the end of the day, Apple's claims that the display outresolves the human eye are good enough for us.
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Stuka87 - Wednesday, June 30, 2010 - link
Yet another top notch, in depth review Anand. I love the amount of depth you add to any review.One question, on the first page you refer to the SoC used in many Android devices as "Scorpion" rather than "Snapdragon." Is there an actual difference, or just different names for the same device? Or perhap Scorpion is more specific to the revision?
I am still thinking that for now I will keep my 3GS. next year when its time to upgrade, a new better iPhone will be out anyway.
Spoelie - Wednesday, June 30, 2010 - link
Scorpion is the CPU, Snapdragon is the entire SoC (with gpu etc etc)brandonicus - Wednesday, June 30, 2010 - link
Still reading the review, but from the first page pictures I have to ask...Did you already scratch your iPhone to hell? When seeing the front side comparison with the Nexus One I thought the iPhone looked terrible. Bad pictures? Or does it just scratch really easy?...I'm sure later in the review I'll read that you threw it on the ground a few dozen times :)ipredroid - Wednesday, June 30, 2010 - link
Many of your in-depth reviews have helped me decide on how to customize/purchase/learn about a product. Nevermind people saying you (Shimpi) are bias towards a product. People are just annoyed at anything Apple related because the media won't shut up about Apple. I realize you are smart enough not to respond to random haters and treat those here with respect and even respond to comments or questions. Thank you to the AnandTech team!The0ne - Wednesday, June 30, 2010 - link
Don't be a fool, many of us here are here at Anandtech because first many of us do like Anadtech ever since he started his site, secondly the reviews are good in general and lastly because most of us are either engineers or in the computer related field.What most of us criticized are valid to some extent. What I've criticized is immensely valid. Do the test and write the review without any type of unjustified opinions included. And if it's not too much trouble be CONSISTENT. I don't go around testing similar products every which way. I'm not saying Anandtech does this all the time but I get really annoy when things are not consistent from one review to the next; meaning testing was not consistent and thus results could be dark matter for all I know.
ipredroid - Wednesday, June 30, 2010 - link
You Proved my point, you randomly hated on a general comment I made, (which I made to no one in particular). No one here is a fool. Base your opinions off of facts not general assersens of which you are speculating. Misplaced criticism based on speculation is for tabloids. Which is unfortunately how you come across when you call people fools and bash with out facts. I'm sure you realize how Hypocritical you are being. You are entitled to your opinion of course but your ignorance shows when you don't base off of facts. (Referring to antenna issue) Apple and Google are both guilty of faulty antennas saying either company's engineers didn't test properly is just silly.The0ne - Thursday, July 1, 2010 - link
Your comprehension is misplaced. When I called you a "fool" it was in referenced to you saying."Nevermind people saying you (Shimpi) are bias towards a product. People are just annoyed at anything Apple related because the media won't shut up about Apple. I realize you are smart enough not to respond to random haters and treat those here with respect and even respond to comments or questions. Thank you to the AnandTech team!"
In short you are saying that some of us that have differing opinions on the subject matter are idiots and that Anand is smart to avoid us and our lame comments. That is pretty much your entire take on it. All I'm saying is that there are many professionals as members here on Anandtech, many of which are very intelligent. Assuming we're that dumb is foolish, and hence the use of the word "fool."
I'm sorry, this Antenna issue is a laughing stock to any respectable engineer. If could have only gone into the finish product by decisions made against the respectable Engineer(s). Whether you choose to believe otherwise is irrelevant because the FACT remains the problem is a basic one. Whether it's Apple, Google or our company is irrelevant as well. The discussion here is Apple iphone, thus the blame is directed at Apple. That does not imply it is ONLY Apple that does this.
And lastly where do you get off telling me I'm ignorant because of my "hate." Where is this hate you are talking about? You're making things up to justify your own means to have something to say to me, less the lack of comprehension in the first place. As for what I've said, that is very general. Why is asking "Do the test and write the review without any type of unjustified opinions included" full of hate?
Sorry you got the wrong idea of my original response.
ipredroid - Thursday, July 1, 2010 - link
I never said you were ignorant because of your hate... read it again... lol. Ignorant for calling me a fool and baseless facts (thank you for the apology). I even stated you ( everyone is) entitled to their opinion. Just stating some people comes across as "haters". People complain about everything, it is easier to see the bad rather than the good, human nature maybe.Anyways, I could careless, meant it as a thank you of sorts to the AnandTech team. Not to belittle other bloggers posts. To the overly negative with out sensible reasoning, yes. You, no. I enjoy reading others posts and rarely comment. I did this time because work put into the review by the AnandTech team seemed to be under appreciated in this review and I commented.
Of course anyone that runs a business isn't going to respond to distasteful posts rudely that wouldn't be smart. Not that those who are "haters" are idiots, even though they certainly can be.
IKeelU - Wednesday, June 30, 2010 - link
I liked the review. It seemed objective to me and I appreciate that the phone and OS were covered separately.Something that wasn't addressed: will the straight edges of the iPhone4 cause damage to one's pants (or one's purse)? My old Sony Ericsson candybar phone actually caused damage to the lining of my left pocket after several months of use. It seems like the iPhone4's edges are the sharpest-ever in a phone...
Though I must disagree about the iPhone 4 making the N1 look dated. In those photos, at least, the N1 looks way sexier to me.*
* I own an N1 ;)
tdream - Wednesday, June 30, 2010 - link
First of all calling the iphone 4 styling uptodate just because its new doesn't make any sense. Jobs says its like an OLD Lecia camera... The 3GS doesn't look dated in the objective sense. If you were to place these two devices in a test, a control group and another which was bombarded with marketing spiel (like the world has) you would get a vastly different viewpoint. Sharp edges are out, just because Apple have run out of ideas decided to be different doesn't mean it's better. Eg glossy vs matte, Apple have made matte cool again... even though all of my monitors are matte. Apple will do anything to be different and stand out, doesn't make it better though.Once again you ignore your own data and say the IPhone 4 is better than the 3GS even though in every case you tested it CLEARLY isn't. It a problem, you know it, Apple knows it, and now everyone in the world knows it. You "feel its better", well then if you feel it then I must feel it too right. Glad we live in a world which values science and facts too. Sorry but you're falling into Apple's main ploy right here, it's magical...
However the rest of your article remains fairly objective and up to your old high standards.