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
More Display
It's obvious how Apple settled on 960x640; it's four times the resolution of the previous iPhones. However, instead of decreasing text size, iOS 4 scales appropriately, and the size of everything remains the same. The result is that there are small details everywhere that pop out. Apple's icons on the home screen are the first that really pop out, and new iOS 4 optimized applications will bring that increased detail as developers add higher resolution artwork.
The display panel itself uses a subset of IPS (In Plane Switching) display technology called Fringe Field Switching (FFS). Where IPS switches the crystal polarization in the plane of the display with two opposing electrical substrates composed of semi opaque metals (which decreases transmission and viewing angles), FFS uses considerably less metal by arranging the electrodes in a comb like structure.
See that - it almost looks like a comb. Or an impulse train. Or Dirac comb. So many combs.
The result is that there's considerably less metal in back and in front of the pixel, resulting in much higher transmission of light through the display, and higher brightness for a given backlight level. Using FFS to drive pixel switching is critical here because of the high dot pitch in the iPhone 4's display.
The other interesting difference between iPhone 4's retina display and previous displays is that the digitizer is in optical contact with the display itself. There's no longer an air gap, and as a result, no longer any opportunity for dust to gradually work its way inbetween. Over time, I've noticed a few dust specks creep in on my 3GS, it does happen. The digitizer and display panel are essentially laminated together. The added benefit is that fewer material interfaces results in fewer internal reflections - think the "super" in Super AMOLED but applied to TFT. That's what Apple has done here.
Apple is using Corning's Gorilla glass which touts hugely increased scratch resistance and robustness. Both the front and back of the iPhone 4 are that same type of glass. I've noticed a few superficial scratches (called sleeks) that have appeared on the back, but really the true test will be how the phone looks after 6 months in the pocket. It's interesting that the iPhone capacity markings have disappeared from the back of the phone - no doubt this was done so Apple could make one part and one part only for each color.
The rest of the details are in the specifications. Apple advertises increased brightness of 500 nits and a contrast ratio of 800:1. We measured, and our iPhone 4 exceeded specs at 571 nits and just under 1000:1 contrast ratio.
Note that the HTC EVO 4G is missing as Anand has it, but it's on its way to me. As soon as I get it, I'll measure display brightness, black point, and contrast and update these results. In addition, the HTC Droid Incredible (and thus Nexus One) contrast is effectively infinity by the way we calculate, due to pixels being completely turned off in the black state. In addition, I'm led to believe that the AMOLED's PenTile grid throws off our numbers when measuring brightness. I've run and rerun this test, it keeps coming up that way.
Next to the iPhone 4, the 3GS display really shows its age. It leaks light when displaying black, with an absurdly high black point of nearly 3 nits. Just looking at the lock screen on the iPhone 4 next to the 3GS it's readily apparent how much better blacks are. iPhone 4 easily bests the 3GS but still isn't quite as contrasty as the Incredible or Nexus One AMOLED displays, or the IPS in the Motorola Droid. You do get higher resolution and brightness, however, but nothing is free.
Going from the iPhone 4's display back to the 3GS is pretty painful, but going back to even relatively high dot pitch displays on the desktop is painful as well. Even on the "high resolution" MacBook Pro with 1680x1050 display, displaying an iPhone 4 screenshot at native resolution uses up 91% of the height. If there's one thing I hope the iPhone 4 display does, it's generate demand for 300 PPI level desktop displays - the era of 110 PPI displays being the norm needs to end now.
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Mumrik - Friday, July 2, 2010 - link
Stop that shit. We all know major iPhone (iPod, Windows, Intel CPU etc.) releases matter more for the industry and the majority of people so it is only natural that they put more work into these articles that are going to get more readers. There is one iPhone out there at a time but a gazillion competing Android phones. They can't cover them all like this - that is why they put extra effort into articles that cover Android itself.I say this as someone who has sworn to never own an Apple product.
Henry 3 Dogg - Thursday, July 1, 2010 - link
Re your final comment"Changing the bars visualization may indeed help mask it [the signal drop], and to be fair the phone works fine all the way down to -113 dBm, but it will persist - software updates can change physics as much as they can change hardware design."
From my own tests, I think that you are missing something here.
When you bridge the left corner line and see the signal strength drop, it does so over the course of several seconds. One would tend to assume that this is time averaging in software BUT...
if you make a call in a very weak signal area and then bridge the gap, the call degrades and possibly drops in the same way i.e. over the course of several seconds.
If the whole effect is physics, then the call should degrade instantly - but it doesn't.
Clearly there is a physics effect, but it also appears that the phone software is responding to this physics effect in a manner that makes it more of an issue.
It may/should be possible, by software changes, to make the final signal degradation when the gap is bridged, no more that it is immediately the gap is bridged, and in all honesty that would pretty much close the issue.
Personally I just don't bridge the gap, and then I find, like you did, that I can simply use this phone in places that I've never been able to use a mobile before.
This really is the best phone yet.
John Sawyer - Thursday, July 1, 2010 - link
"It may/should be possible, by software changes, to make the final signal degradation when the gap is bridged, no more that it is immediately the gap is bridged, and in all honesty that would pretty much close the issue."Hopefully this is what Jobs meant when he said, "Stay tuned."
mmike70 - Friday, July 2, 2010 - link
Maybe calls are more forgiving because I haven't had one drop yet. What does happen is when I hold the iphone4 normally in my left hand (I'm right handed, tap with the right hand fingers, hold with the left), the data connection drops immediately. I'm not talking even over the course of five seconds. The currently loading web page will stall the instant I pick the phone up. This is in an area with a very close tower, constant 5 bars on an iphone 4 and 3gs. I can't cradle, grip, pinch, cover, etc the 3gs to make any detectable difference in data performance.chinkgai - Thursday, July 1, 2010 - link
Hey Brian or Anand,Just wanted to point out that on my wireless N/G with the same speedtest.net app tests, my download speed usually always tops out around 10700-11000 kbps, so I'm not sure why you're getting such a low speed on average. It also maxes out my upload speed which is far lower than yours. I'm on a 16/2 line here in Los Angeles.
Great article though!!
bparun - Thursday, July 1, 2010 - link
Obviously a good thorough review. Why is there not a good amount of detail about the newly added Gyroscope in iPhone 4? I have read that its the electronic version of a vibrational one. More on that would be a nice read, as the future of games and apps using this gyroscope for augmented reality would be in abundance. I am sure all the other phone manufacturers are ready to follow, as usual.Mumrik - Friday, July 2, 2010 - link
Such a minor feature in the larger perspective...John Sawyer - Thursday, July 1, 2010 - link
It seems to me, that if the iPhone 4's signal is attenuated when one's hand bridges the gap between the two antennas on the lower left side, but not if one bridges the two antennas by holding the iPhone 4 at its sides, above the gap, that one possible fix for the future, might be to move the gaps so that they're at the topside left and underside left, so one's hand (left or right) doesn't touch the gaps (I doubt many people cover the bottom or top edges of their phones while in use). This would allow the lengths of the two antennas to remain nearly the same, and so it might not compromise the original antenna design's signal strength, unless the original design relies on the upper and lower left corners/ends of the two antennas to be untouched by a user's hand, which would be stupidly unnatural (as nearly everyone notes). If full antenna strength does require these two corners/ends to be uncovered, does this mean the iPhone 4's main radiating signal power, for both antennas, emits from the upper and lower left corners/curved ends of the two antennas, rather than from the entire length of the antennas? If the entire length of both antennas send/receive, moving the gaps to topside left and underside left wouldn't seem to greatly affect the right-side UMTS/GSM antenna's exposure to the world (more critical than the left Bluetooth/wifi/GPS antenna's exposure, since a cell tower is usually further away than a local wireless router, etc.), no matter which hand it's held in (can't say the same for the left-hand antenna, but that may not be important due to closer proximity of wireless routers, etc.); but if the signals for both antennas send/receive mainly from one end of each antenna (currently the curved ends), requiring them to have some uncovered access to the world, then what about moving the gaps closer to the center-top and center-bottom locations? I have a hunch that these potential end-radiating points don't have to be curved, as they currently are at the corners, but maybe I'm wrong. However, this would make both antennas nearly the same length, which might affect signal strength too, if the different frequencies sent/received by the two antennas require their lengths to be as they currently are.
If Apple doesn't want do anything like that (or if the antenna design doesn't allow for it), or even to coat the exposed metal antenna with some kind of clear coat (if that even helps enough), it might be best to move the antennas back inside, wrapped around the inside of the case--I don't think too many users will moan about not being able to touch metal around the sides of the iPhone. Another approach (which would work for either internal or external antennas) might further improve the antenna: two antennas for the phone signal, one at each lower corner (since FCC phone-to-head maximum radio signal level requirements now force manufacturers to put the phone antenna in the bottom of new cellphones), with whichever one that's not covered by the user's hand being used (circuitry in the phone could detect this).
iwod - Thursday, July 1, 2010 - link
1. I dont know why no one mentioned it in their reviews. And only Anand manages to point out my same thoughts, Why no insulation coating on the Stainless steel? It add less then 1mm of thickness and is cheap and easy enough to do so.The only reason would be Apple Engineer were using 3GS casing while they were testing..
2. No one mentioned the new Skyworks Baseband chip. I have never head of them, and dont know how good they are. Wiki shows they have been in the business for nearly a decade now, so that should be good. The Less Drop calls on iPhone 4 were more to do with this Chips instead of AT&T network upgrade. The previous Infineon Chipset were simply poor. It was Infineon first chip into communication and mobile network. And it didn't work well although the problem were easily pointed to AT&T network. It wasn't only AT&T were having drop calls, Every iPhone 3G user in the world were having drop calls with different Network. And the Drop Calls rate for iPhone 3G/3GS on AT&T were much higher then any other phones on AT&T network. That simply points to a problem the lies within iPhone.
3. The iPhone A4 is a package on package SOC. The Memory was Dual Channel Low Power DDR. Why didn't they use Low Power DDR3? It is lower power and faster then ancients DDR.
4. Why didn't Apple upgrade their GPU? The iPhone 4 is 4x as much resolution. Playing Games on it requires much more computational power.
5. 110ppi may not be enough for desktop. But how many ppi would a Retina Display for Desktop and Notebook need? I just measure we are typlically at least 24 inch away from the monitor, double the distance as you would hold on a iPhone. If a iPhone 4 requires 330 ppi, then Double the distance would half the ppi, which means 165ppi, That means 2560 x 1200 Resolution for 18" Display. For a Large Desktop Display 27", you will need 4K ( 4096×1716 ) resolution, which is actually perfect for Digital Film making and Broadcasting. I think it is time we distinguish a Computer Display to Normal TV. They can keep with their 1080P for as long as they want. We want Retina Display on our Mac.
( Notes: However even the lastest DisplayPort 1.2 does not offer enough bandwidth for 4K resolution )
6. Software Side - Some Reports indicate iOS 4.0 uses more memory then older iOS 3.0 which more useless process standby ( Such us Internet tethering and Bluetooth.exe even when both features are OFF ). While they may only consumer 2 - 3MB of memory. It is still a lot on a mobile devices. I hope anand can verify if they have time.
7. Saferi on iOS 4.0 seems to be using a older version of WebKit as well. I am sure SunSpider will run faster and on par with Andriod once Apple update iOS.
brownreese - Thursday, July 1, 2010 - link
I am blown away by the thoughtfulness of this review. Too many sites read like regurgitated press releases. I have just become a lifelong reader. Thanks.