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
Camera Usability
It still takes almost two seconds to activate the camera on the 4, which is enough time to miss whatever it is you’re trying to grab a photo of. Thanks to the iOS 4 update however, the shutter is almost instantaneous. The difference appears to be that the photo is committed to memory but not fully written to NAND, whereas before the photo would be written to the Flash before you could take another picture. Power loss in the middle of snapping photos seems pretty rare on a smartphone so the tradeoff, if I’m correct, makes sense.
Apple opted for a lower noise rather than higher resolution sensor in the iPhone 4 and it did pay off. The main camera shoots photos at 2592 x 1936 compared to the EVO 4G’s 3264 x 1952, but the resulting images are far less noisy - particularly in low light situations:
HTC EVO 4G - Low Light
Apple iPhone 4 - Low Light
The 4’s main camera, like the HTC Incredible and EVO 4G, is a decent replacement for a point and shoot if you’re primarily outdoors. You’re still going to get better image quality out of a good point and shoot, but the tradeoff is convenience. The limitations are significant.
Because you rely on the iPhone 4’s software controlled aperture and shutter speed you don’t have the ability to properly expose the image. You have to rely on Apple’s algorithms, which tend to either overexpose outdoors or miscalculate white balance with non-halogen light sources.
This is an example of a photo taken outdoors that’s more washed out than it needs to be:
And many of you picked up on the white balance issue I snuck into our EVO 4G review yesterday:
Regardless of where I tapped to focus, I could not get the iPhone 4 to set a proper white balance in our photo box.
While I was watching the screen, the iPhone 4 would alternate between yellow and white for the background color. It seemed to be trying to calculate the white point but was just being thrown off by the type of light. If I timed the shot right I could snag the photo while the iPhone was switching between white balance points:
I also had this problem in my office which uses LED can lights.
This is far more yellow than it should be
While Brian didn't have the same problems I did, Brandon Hill (DailyTech Editor in Chief) did. It seems to be very dependent on the type of lighting you have and even then it seems to vary based on the type of CFLs. And unlike the EVO 4G, there’s no way to manually set a white balance on the 4.
For overall image quality though I have to hand it to Apple, the iPhone 4 does do a better job than the EVO 4G or other phones I’ve used. Take a look at this shot inside my house:
The colors in the iPhone 4 shot are on point. The green is correct, the wooden floor is right and the black is, well, black. The EVO 4G didn’t do so well on this test by comparison:
The 4’s camera isn’t perfect, but it does appear to handle colors better than the EVO (with the exception of my white balance issue) and delivers lower noise photos.
Compared to other phones the 4 does similarly well, besting the 5 megapixel camera in the Motorola Droid easily in terms of color reproduction and sharpness. Though the HTC Incredible previously was a top performer alongside the N900, the iPhone 4 makes the Incredible look a bit oversharpened and artificial. Compared to the 3GS, the iPhone 4's improvement is obviously dramatic, as shown in the gallery below.
Video is recorded at 1280x720, in H.264 with AAC mono audio. We measured a bitrate of 1.35 MBps, outclassing all the other smartphones we've tested.
iPhone 4
HTC Droid Incredible
Motorola Droid
Nokia N900
What's interesting is that the iPhone 4 appears to crop the sensor down for video recording, taking the center most 1280x720 pixels instead of scaling down the entire image size. The result is that the focal length for video recording is notably longer than when taking photos.
You can see the difference is quite notable standing in the same place. Perhaps the A4 SoC lacks the compute power to apply a scale and encode at the same time, necessitating this crop. Whatever the case, video shot with the iPhone 4 still looks very good at the promised and delivered 30 FPS. Move the camera around enough, and there's still screen door effect from the rolling shutter like any CMOS sensor is going to give you - it's a fundamental problem no phones are going to get around soon. Its also right there in the specifications page for the camera SoC; rolling shutter.
Similarly, iPhone 4 does give you 5x digital zoom, though we still maintain you're better off taking photos at native resolution and messing with them later with better interpolation algorithms.
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Brian Klug - Wednesday, June 30, 2010 - link
You know, I realized that seconds after writing it and decided that it'd just be too much to go into a detailed explanation. I corrected it to something much simpler ;)-Brian
zerosomething - Wednesday, June 30, 2010 - link
Fantastic article thanks for the in-depth review.From the article on page 5. "...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."
There is actually a Model number on the back of mine. So there will need to be 4 different backs. However they can make one part for each color for the fronts. In reality they will have to make 2 fronts and 4 backs to cover all capacities and colors which is one more than they had to make for the 3G/GS phones.
Wow I'm picking such tiny nits in a fantastic article. Guess everything else was so through this one stood out.
Shadowmaster625 - Wednesday, June 30, 2010 - link
If you already own an iPhone, how is it worth it to upgrade? You said so yourself... tiny text is still tiny. So what are you getting for hundreds of dollars that the 3GS doesnt give?Guspaz - Wednesday, June 30, 2010 - link
I'm a 3GS owner in Canada (Fido is my provider), so we've had tethering ever since iOS 3.0 launched roughly a year ago. I noticed two small errors in the discussion on tethering, and felt one thing was possibly mischaracterized.First, I'd like to give a brief mention of how tethering works with Fido (and other Canadian providers). We've always had data caps on our iPhone data plans. Typically, you get something vaguely like 1GB for $30, but both the 3G and 3GS launches featured limited-time 6GB for $30 offers that are permanently grandfathered.
Fido/Rogers policy is that all users with a 1GB dataplan or higher get free tethering (this appears to be a permanent position), which uses the same data cap. So, in effect, the vast majority of Canadian iPhone owners have tethering.
The first error is "With the iOS 4 upgrades the iPhone 4 supports tethering over Bluetooth or USB." Tethering is not new in iOS 4; it's been supported since iOS 3, and tethering support is identical in iOS 4.
The second error is "You also need to either have Bluetooth enabled or be connected via USB to the computer you wish to tether." Firstly, Bluetooth doesn't need to be enabled before enabling tethering. If you enable tethering while bluetooth is disabled, a prompt appears asking you if you want to enable bluetooth, or just tether over USB. Secondly, not really an error but an important clarification: on Windows, you can only tether via USB with a computer that has the iPhone tethering drivers installed.
These tethering drivers are bundled with iTunes, and cannot normally be installed separately, but iTunes and the drivers have separate uninstallers in Add/Remove Programs. This means that you can set up, say, a friend's laptop to tether via USB by installing iTunes and then uninstalling iTunes, leaving the drivers behind. Annoying, but workable if bluetooth is unavailable.
In terms of the mischaracterization, the performance of tethering is called into question. This may be an AT&T networking issue, as I've not experienced the performance issues. Generally, whatever the networking performance my phone is achieving, a tethered computer will also achieve. There is no difference between the two, so any connectivity issues are strictly network-related rather than tethering-related. Performance is generally good; latency is usually 130-150 to a close remote host, and downstream bandwidth is 1-5 Mbps depending on congestion/location. Upstream, since the iPhone 3GS lacks HSUPA, is limited (335Kbps in practical tests), but tends not to vary quite as much as downstream based on signal quality.
Upstream performance isn't stellar, but it is relatively reliable, if a tad slow. Packetloss is rare if the phone has a good signal. I regularly use tethering to get laptops connected on the road, and remote desktop over a tethered connection is very snappy, and is amazingly faster than on-device RDP.
Mike1111 - Wednesday, June 30, 2010 - link
@Anand:"Even if you just cover the camera it’s actually better to make calls over FaceTime than 3G based on the sound quality alone."
Cover the camera? Why? Just press Home and you have a traditional voice-only VoIP call with reduced bandwidth.
Also I would like to see some comparison to the competition. Video calling on phones exists for quite some time. How about a comparison of video and voice quality?
And in regard to the bandwidth requirements, would it have been realistic to allow FaceTime over 3G?
You also mention that the compression is too high for text, is that because of a bad compression algorithm or codec, too low resolution or bandwidth? Is that something that realistically could have been done better?
strikeback03 - Thursday, July 1, 2010 - link
Does returning to the home screen actually kill the camera? That would be annoying if you only wanted to look at your calendar or something else on the phone while in a video call.Mike1111 - Thursday, July 1, 2010 - link
As with a normal (cellular) call you can always resume the video by tapping on the green status bar (call active...).Oyeve - Wednesday, June 30, 2010 - link
How is the sound quality? Is there an EQ (missing from all things "i")bkman - Wednesday, June 30, 2010 - link
An interesting review but flawed by bad metrics. The authors confuse absolute power measurement, dBm, with relative power measurement, dB. For example, a signal strength drop from -51dBm to -83dBm is not a drop of 24dBm, it is a drop of 24dB.hgoor - Wednesday, June 30, 2010 - link
Hi, I loved the review: really (and mean really) thorough! Thanks for that.However: unless I blacked out while reading and missed it: what about the noise canceling microphone? How does that work? I guess it's not that noticeable as you only mention it one time?
I'm very curious to find out if it's a feature that helps? Also: I wonder if it can be used for listening to music? I have an expensive pair of headphones from Sennheiser, but I wonder if it can be used (in the future?) to help listen to music (and on/or on the phone) when you have a lot of ambient noise?
Would be nice if you could clear that up. Also: I wonder how the iPhone 4 holds up against the new Samsung 1ghz powerhouse?
Keep up the good work!