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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scarnie - Thursday, July 1, 2010 - link
See my article here: http://bit.ly/5pxjgkBasically, the iPhone 4 is about 33% faster than the 3GS (600MHz) and 25% slower than iPad (1GHz) putting it squarely at 800MHz.
Cheers,
Stu
heri16 - Thursday, July 1, 2010 - link
Since it has been confirmed that Apple would not be able to beat physics, the best way for them is to issue a firmware update to hide the signal loss in terms of bars (GASP!) . Since after-all, calls won't be dropped at one bar, why make us all worry?From my tests, attenuation by water-containing bodies is always a problem to RF. My best way around has been using micro-strip circular polarized antennas to reduce the effect. I've been using such antennas to cut 2.4Ghz signals through dense trees, which have "waterly" leaves. It also works better in rainy conditions compared to linear antennas.
(My tests shows reduction in attenuation by 70% in dbm units for my modded 2.4Ghz enterprise router through those same trees.) This will work since our hands/bodies are "waterly" too.
My suggestion to Apple to is have both thin circular-polarized micro-strip antennas embedded in the back surface, and linear polarized antennas at the sides, and diversity-RF controllers to get improved best-case and worst-case performance.
I'm not sure whether an iphone accessory maker can create the same fix through a paper-thin antenna plugged in.
heri16 - Thursday, July 1, 2010 - link
Here are some links to help understand the iphone RF fix.http://en.wikipedia.org/wiki/Circular_polarization
http://en.wikipedia.org/wiki/Microstrip_antenna
NordicNINE - Thursday, July 1, 2010 - link
I finished up work & school for the day and just popped down to relax. Brought up my favorite tech news site and started the recorded DVR shows. I pulled up this article and then the recording of the new Futurama started up.Xeeros - Friday, July 2, 2010 - link
Not to nitpick but The Incredible has 8GB internal PLUS the microSD which Verizon gives you a 2GB stick so it would be 10GB stock as they now package the SD card in the phone. Had a Launch unit and the refresher that says Droid on the box versuses the HTC incredible box. ONly difference was my store gave me a card for the 2GB and now its pre-packaged. To be honest most review sites that have it listed in comparison have it labeled this way, so probably not your fault.sporadic - Friday, July 2, 2010 - link
A question though:When you ran your PDF download tests were you using any encryption or was this on an open network?
dhvanii - Friday, July 2, 2010 - link
This is a great article on i4 antenna and DL reception. I have a few questions.1. if you take 1.5 MHz channel bandwidth, then the lowest signal strength measurable should be around -112 dBm. But this WCDMA and so if it is 4.5 MHz the lowest RSSI should be -107 dBm. Add to that a 4-6 dB noise figure and the lowest RSSI should be around -100 dBm. How is the device reporting -113 dBm for 3G ? Is that only for GSM reception where it is 200 KHz channel bandwidth and so theoretical lowest is around -120 dBm ?
2. How about UL ? What is the Max Tx Power of this device ? 23 dBm ? How is that affected by this antenna glitch. Radio link protocols requiring UL acks for DL packets will definitely get affected by this poor antenna performance if UL is also affected.
Thanks again for your detailed analysis.
navderek - Friday, July 2, 2010 - link
Well I'm glad we agree...to be honest I did not read the entire article, but only the section about the antenna issues with the handset.I did not see you bring up the point of CQI, nor did I see you mention that RSSI is really not a good measure for network coverage / quality (when used alone). Perhaps you've mentioned it in other articles, and if so a link to those would have been warranted for charities sake.
Have you ever considered writing up an article about how the air interface works? I think everyone would be much further ahead if they had a good basic understanding of the air interface and how the handset communicates with the BTS...especially now with so many networks competing it would put a little more power into the consumers hands to judge the quality of the network rather than rely on their silly marketing adds and crappy signal strength bar displays.
Finally, you said that at -107dB the iPhone4 "deals just fine" with it. Do you have data to back that up? What kind of data rates were you getting? I'd be surprised if you could even hit 1MB/s.
Just so you know, I work for TELUS Mobility in Canada. We have the first TRUE "all IP" network running in North America. We launched back at the end of 2009 with a 3.5G network. In my area we use NSN equipment and in practical use you can easily get sustained data rates greater than 10MB/s (downlink, theoretical = 21MB/s). We are also talking latencies of less than 50ms and almost no jitter....how did we do this? Well we are the only company in North America to have built the network from the ground up using IP transport all the way to the radios. We have fiber going to every single tower which serves only this 1 network (we have 2 others to manage as well, PCS / iDEN). :-) I'm not trying to prop-up my company or anything, but just giving a hint as to why other carriers such as AT&T have so many problems with their "patchwork" network which still most likely uses legacy copper circuits multiplexed and converted into IP packets...this puts significant strain on the core to keep up with the demands.
If people understood the air interface protocols in a general and basic sense at least they could judge the quality of this part of the network and then focus on looking into the other parts...I just find it frustrating that most people who don't understand how it works tend to give the network a "basket" rating based on simple RSSI measurements which does not really give much insight except as to how much radiation your standing in.
zmslink - Friday, July 2, 2010 - link
So the net effect is that iPhone 4 drops fewer calls then the 3GS despite losing as much as 24dB when held "incorrectly," but does that signal loss affect battery life much?davidcjones - Friday, July 2, 2010 - link
It is amazing how someone can do such detailed research to get to the bottom of this!Thanks for your hard work. Of course, I am distressed that people are so inclined to run to the courts to file class action suits before they actually investigate the issue in detail...
David Jones
Jericho, VT