Apple iPhone 4S: Thoroughly Reviewed
by Anand Lal Shimpi & Brian Klug on October 31, 2011 7:45 PM EST- Posted in
- Smartphones
- Apple
- Mobile
- iPhone
- iPhone 4S
Video Capture Quality
The iPhone 4 shot excellent quality 720p30 video and remained arguably the best in that category for a considerable run. Recently though it has been outclassed by smartphones that are shooting 1080p30 with impressive quality which record 720p30 just as well. The 4S catches back up on paper and likewise can capture video at 1080p30. Like every prior iDevice, there are no toggles to change video capture size - it’s always at the device’s maximum quality - 1080p30. Apple also made note of their own gyro-augmented electronic stabilization which the 4S brings. Practically every other smartphone we’ve seen has likewise included some electronic stabilization which leverages the pixels around the target 1080p or 720p area.
We’ve captured videos from the 4S in the dual camera mount alongside the 4, an SGS2, and a reference Canon Vixia HF11 for comparison. I also shot a low light comparison between the 4 and 4S. Showing the differences in video between all of those is something of a challenge, so I’ve done a few different things. First, you can grab the native format 4S versus 4 videos here (442 MB) and the 4S versus SGS2 video here (289 MB).
It’s hard to compare those side by side unless you have multiple instances of VLC open and hit play at the same time, so I also combined and synchronized the comparison videos side by side. The frame is 4096x2048 so we can see actual 1080p frames side by side. Though I realize 4K displays are hard to come by, you at least can see full size images which I’ve synchronized.
It’s readily apparent just how much more dynamic range the 4S has over the 4 when you look at the highlights and dark regions. In addition, the 4S does indeed have better white balance, whereas the 4 changes its white balance a few times as we pan left and right through different levels of brightness and ends up looking blue at the very end of the first clip.
Then comes the SGS2 comparison, and I start out with some unintentional shake where you can really see the 4S’ anti shake kick in. I considered the SGS2’s electronic anti shake pretty good, however its narrower field of view in 1080p capture exacerbates the shaking. Subjectively the two are pretty closely matched in terms of video quality, but the SGS2 runs its continual auto focus a lot and has a few entirely unfocused moments. The 4S’ continual auto focus is much more conservative and often requires a tap to refocus.
The Vixia HF11 comparison gives you an idea how the 4S compares to a consumer level camcorder shooting in its own maximum quality mode. I’d say the 4S actually gives it a run for its money, surprisingly enough, though the 4S (like every smartphone) still has rolling shutter in movement. Finally I shot a low light side by side with the 4S and 4, again white balance is better, but the 4S video in this mode looks a bit noisier than the 4. In addition, the 4S exhibits more lens flaring (something I noticed while shooting stills as well) than the 4.
Subjectively video quality from the 4S is very good, but it falls short in other ways. The 4S shoots video at 1080p30 baseline with 1 reference frame at 24 Mbps, with single channel 64 Kbps AAC audio. If you’ve been following our smartphone reviews, you’ll know that although this is the highest bitrate of any smartphone thus far (Droid 3 we’ve seen at 15 Mbps, SGS2 at 17 Mbps), it’s just baseline and not high profile we’ve seen on Exynos 4210 or OMAP4. In addition, two channel audio is becoming a new norm.
Media Info from video shot on the iPhone 4S
The result is that Apple is compensating for lower encoder efficiency (quality per bit) by encoding their 1080p video at a higher bitrate. Other players are getting the same quality at lower bitrates by using better high profile encoders. We dug a little deeper with some stream analysis software, and it appears that Apple’s A5 SoC is using the same encoder as the A4, complete with the same CAVLC (as opposed to CABAC which the other encoders in OMAP4 or Exynos 4210) and efficiency per frame size. It’s just a bit unfortunate, since the result is that video shot on the 4S will use ~40% more space per minute compared with 1080p30 video shot on other platforms (180 MB for 1 minute on the 4S, 128 MB for 1 minute on the SGS2, and 113 MB for 1 minute on OMAP4).
| iPhone 4S | iPhone 4 |
One last thing to note is that Apple roughly keeps the same cropped field of view size as the 4 on the 4S when shooting video. You can see this behavior in the rollover above. The 4S field of view is just slightly narrower than the 4. Note that the actual area reported from the sensor when in video capture mode is almost always a crop (sometimes with a 2x2 binning) of the full sensor size with some pixels around the frame for image stabilization.
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Pata - Tuesday, November 1, 2011 - link
Will these factors (bluetooth and gps) be incorporated in future tests? I now keep bluetooth and the gps on for Siri and geofenced reminders. I'm guessing that Android phone users might be soon be using bluetooth more often as well, given all the bluetooth watch accessories that will soon be available for their platform. With bluetooth and gps left on, with find my friends, reminders all running in the background, my iPhone usually doesn't last anywhere up to 9 hrs of usage.DukeN - Tuesday, November 1, 2011 - link
Thanks Anand for reviewing every single Apple, iOS, Android/Droid major and minor update since the summer. How about we perhaps devote 2 frickin pages to cover/preview/benchmark some of the newest Blackberry devices?Heck you even covered turds like the HP Veer, and Windows Phone devices.
Perhaps we can devote a couple of pages to the smartphones that have a quarter of the market?
Thanks
jamyryals - Tuesday, November 1, 2011 - link
Even as a [forced] Blackberry user, I'd rather they didn't spend their time reviewing Blackberry devices.Also, it is "biased" in that case.
SicMX - Tuesday, November 1, 2011 - link
Fantastic review, keep up the good work!PS. Especially appreciated the in-depth review regarding the camera + image quality.
Matt Campbell - Tuesday, November 1, 2011 - link
Nice article Brian, Anand. One clarification for Page 8, Siri can't read emails - only incoming (new) text messages. She'll tell you this herself if you ask her to read your emails :)And one comment, the addition of Bluetooth 4.0 is a big leap forward in my opinion. The Bluetooth stack in every other iPhone revision was missing the Serial Port Profile stack, which severely limited hardware developers. Since the 4S is "Bluetooth Smart Ready", it should support all kinds of fun new sensors and gadgets without the need for additional hardware.
_tangent - Tuesday, November 1, 2011 - link
Great in depth review! Anandtech is one of the only places you can find this sort of analysis, and for the technically minded consumer, it's an invaluable resource. Kudos!I'm a bit confused by the GPU arms race in the mobile space. Aren't we reaching a point where the screen is small enough and far enough away from your face that the law of diminishing returns applies? Unless the ultimate objective is to have us all connect our phones to tvs or other displays for gaming on a larger scale.
I'm not sure where i stand on mobile gaming these days. I have a relatively capable android handset, but find myself not even playing the 3D games already available. Not because they aren't good or pretty enough, just because intensive 3d gaming slams my battery, is less well suited to the odd 5 minute opportunity i get to game on the go, and the lack of physical controls for more "conventional" games is often frustrating. In any case, having lived with the handset for 6 months or so, i'm not clamoring for better 3D performance. Maybe plenty of people are though.
I'm not personally a fan of Apple products. Not because they don't offer a great UX and aren't well polished in their own right, but because the cost apparently associated with that is too high. As a software developer by trade I find their draconian, fascist approach to the appstore and development in general somewhat distasteful. I don't equate choice and flexibility with complexity. That said, i don't mind Apple in a world where they have competitors offering an alternative philosophy This drives everyone to innovate which is great for us as consumers.
Hopefully ICS will bring Android up to par with iOS from a UX point of view, whilst retaining the flexibility and customization that much of it's user base has come to appreciate. I look forward to a similarly comprehensive look at the Galaxy Nexus and other ICS phones as they're released!
Shinobi123 - Tuesday, November 1, 2011 - link
Why is the New Razr missing from most of the graphs? It was in the first few, basically the only reason I kept reading this article.. But it wasn't included in any. :(tipoo - Tuesday, November 1, 2011 - link
They probably aren't done testing it.rimshaker - Tuesday, November 1, 2011 - link
As usual, the very best in depth product review available. As a EE, no review is ever thoroughly complete until I read it here on Anandtech. Wonderful!My only question is how to display the numerical wifi RSSI without using 3rd party apps? I tried it in field test mode but the wifi icon never changes like the cell signal does.
dubthedankest - Tuesday, November 1, 2011 - link
I second this question as well as the one prior on how to enable the numerical RSSI for WiFi - that would be very helpful.Great review!