Camera

The iPhone 5s continues Apple’s tradition of sensible improvements to camera performance each generation. I was pleased to hear Phil Schiller deliver a line about how bigger pixels are a better route to improving image quality vs. throwing more at the problem. I remember hearing our own Brian Klug deliver almost that exact same message a year earlier when speaking to some engineers at another phone company.

The iPhone 5s increases sensor size compared to the iPhone 5. Last week Brian dug around and concluded that the 5s’ iSight camera sensor likely uses a format very similar to that of the HTC One. The difference here is while HTC opted for even larger pixels (arriving at 4MP), Apple chose a different balance of spatial resolution to light sensitivity with its 8MP sensor.

One thing ingrained in my mind from listening to Brian talk about optics is that there is no perfect solution, everything ultimately boils down to a selection of tradeoffs. Looking at Apple/HTC vs. the rest of the industry we see one set of tradeoffs, with Apple and HTC optimizing for low light performance while the rest of the industry chasing smaller pixel sizes. Even within Apple and HTC however there are differing tradeoffs. HTC went more extreme in pixel size while Apple opted for more spatial resolution.

iPhone 4, 4S, 5, 5S Cameras
Property iPhone 4 iPhone 4S iPhone 5 iPhone 5S
CMOS Sensor OV5650 IMX145 IMX145-Derivative ?
Sensor Format 1/3.2"
(4.54x3.42 mm)
1/3.2"
(4.54x3.42 mm)
1/3.2" ~1/3.0"
(4.89x3.67 mm)
Optical Elements 4 Plastic 5 Plastic 5 Plastic 5 Plastic
Pixel Size 1.75 µm 1.4 µm 1.4 µm 1.5 µm
Focal Length 3.85 mm 4.28 mm 4.10 mm 4.12 mm
Aperture F/2.8 F/2.4 F/2.4 F/2.2
Image Capture Size 2592 x 1936
(5 MP)
3264 x 2448
(8 MP)
3264 x 2448
(8 MP)
3264 x 2448
(8 MP)
Average File Size ~2.03 MB (AVG) ~2.77 MB (AVG) ~2.3 MB (AVG) 2.5 MB (AVG)
From Brian's excellent iPhone 5s Camera Analysis post

Apple moved to 1.5µm pixels, up from 1.4µm in the iPhone 5. Remember that we’re measuring pixel size in a single dimension, so the overall increase in pixel size amounts to around 15%. Apple also moved to a faster aperture (F/2.2 vs. F/2.4 on the iPhone 5) to increase light throughput. The combination can result in significantly better photos than the outgoing 5 when taking photos in low light.

iPhone 5/5c Low Light

iPhone 5s Low Light

With the move to larger pixels, Apple has done away with its 2x2 binning mode in low light settings. The iPhone 5 would oversample each pixel after scene brightness dropped below a certain threshold to improve low light performance. The oversampled image would then be upscaled to the full 8MP, trading off spatial resolution for low light performance. The iPhone 5s doesn’t have to make this tradeoff. In practice I didn’t find any situations where the 5s’ low light performance suffered as a result. It always seemed to produce better shots than the iPhone 5.

iPhone 5/5c

iPhone 5s

Unlike some of the larger flagships we’ve reviewed lately, the iPhone 5s doesn’t ship with optical image stabilization (OIS). We’ve seen devices from HTC, LG and Nokia all ship with OIS, and have generally been pleased with the results. It’s not a surprise that the 5s doesn’t come with OIS as it’s largely the same physical platform as the outgoing 5. Still it would be great to see an Apple device ship with OIS. Perhaps on a larger iPhone.

As is always the case in space constrained camera systems, what Apple could not achieve in the physical space it hopes to make up for computationally. The 5s leverages electronic image stabilization as well as automatic combination of multiple frames from the capture buffer in order to deliver the sharpest shots each time.

Apple’s cameras have traditionally been quite good, not just based on sensor selection but looking at the entire stack from its own custom ISP (Image Signal Processor) and software. With the A7 Apple introduces a brand new ISP. Although we know very little about the new ISP, you can find references to Apple’s H6 ISP if you dig around.

Apple continues to ship one of the better auto modes among smartphone cameras I've used. I still want the option of full manual controls, but for most users Apple's default experience should be a very good one.

Capturing shots under iOS 7 is incredibly quick. Shot to shot latency is basically instantaneous now, thanks to a very fast ISP and the A7’s ability to quickly move data in and out of main memory. It’s impossible to write shots to NAND this quickly so Apple is likely buffering shots to DRAM before bursting them out to non-volatile storage.

 

The new ISP enables a burst capture mode of up to 10 fps. To active burst mode simply hold down the shutter button and fire away. The iPhone 5s will maintain a 10 fps capture rate until the burst counter hits 999 images (which was most definitely tested). Although it took a while to write all 999 images, all of them were eventually committed to NAND.

Photos captured in burst mode are intelligently combined as to not clutter your photo gallery. The camera app will automatically flag what it thinks are important photos, but you’re free to choose as many (or as few) as you’d like to include in your normal browsing view. Since all of the photos captured in burst mode are physically saved, regardless of whether or not you select them to appear among your photos, you can always just pull them off the 5s via USB.

The rear facing camera is paired with a new dual-LED True Tone flash. Rather than featuring a single white LED to act as a flash, Apple equips the iPhone 5s with two LEDs with different color tones (one with a cool tone and one with a warm tone). When set to fire, the 5s’ ISP and camera system will evaluate the color temperature of the scene, pre-fire the flash and determine the right combination of the two LEDs to produce the most natural illumination of the subject.

I’m not a huge fan of flashes, but I have to say that in a pinch the True Tone flash is appreciably better than the single LED unit on the iPhone 5. Taking photos of people with the new True Tone flash enabled produces much warmer and more natural looking results:

True Tone Flash Enabled

Even if your subject happens to be something other than a person I’ve seen really good results from Apple’s True Tone flash.

I still believe the best option is to grab your photo using natural/available light, but with a smartphone being as portable as it is that’s not always going to be an option.

I have to say I appreciate the vector along which Apple improved the camera experience with the iPhone 5s. Improving low light performance (and quality in low light situations where you’re forced to use a flash) is a great message to carry forward.

Front Facing Camera

The iPhone 5s and iPhone 5c share the same upgraded front-facing FaceTime HD camera. The front facing camera gets a sensor upgrade, also with a move to larger pixels (1.9µm up from 1.75µm) while resolution and aperture remain the same at 720p and F/2.4. The larger sensor size once again improves low light performance of the FaceTime HD camera (iPhone 5 left vs. iPhone 5s right):

Battery Life Video
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  • BrooksT - Wednesday, September 18, 2013 - link

    Nobody will disagree because you've completely destroyed your credibility by insulting the credibility, integrity, and competence of the reviewer, the site, and Apple because the evidence doesn't conform to your speculations and bias. You are not to be taken seriously, and at this point I think everyone sees that.

    Post evidence of this conspiracy or STFU.
    Reply
  • ddriver - Thursday, September 19, 2013 - link

    How a whiff of reality for you - my credibility is and has not been on the line on this one. You don't know who I am, you don't know my credentials. This is not the case for Anand, even if I am right he is not in the position to admit to compiling the review in a manner that creates an unrealistically good presentation of a product, because unlike for me, that would be a huge credibility calamity for him. If anything, his responses are very "political" carefully dancing around the pivot points of my concerns. While his response did partially bring light to a few of my concerns, my key points remain valid - the article continues to not compare A7 with ARMv7 head to head in the sole native CPU benchmark present in the article, "CPU performance" was not renamed to JS performance or moved to browser performance or something like that. See, just because he didn't agree with my points and admit to being biased does not mean I am wrong and that is not the case, considering he is not in the position to do that. I didn't really expect anything more or less than the same "carefully dancing" answer as the article itself, my main motivation was to show him that not all AT readers are incapable of reading between the lines, for the sake of future articles, I did not expect that he would make any revision to the article at hand. Honesty is for those who have nothing to lose, and while his credibility is no the line, my isn't, make the conclusions, if you can ;) Reply
  • CyberAngel - Thursday, September 19, 2013 - link

    Don't worry! I believe you...conditionally!
    I put it this way: I greatly doubt that the tests would reveal any points that are less than favorable the Apple. ANY company would do the same: promote the best parts and highlight the strength of the product.
    Reply
  • akdj - Thursday, September 19, 2013 - link

    "You don't know who I am, you don't know my credentials."
    I'm not sure anyone here is interested---you've already made clear you're a conspiracy theorist, that you believe Apple is paying off reviewers, that you disrespect folks MUCH more intelligent than yourself when it comes to chip architecture...and that your "main motivation was (Is) to show him that not all AT readers are incapable of reading between the lines". You've shown NO one ANYthing substantiated. You continue to argue baseless facts and accuse respected individuals and groups/teams of intelligent members of being bias towards Apple. Nothing in this review supports your claims---NOTHING! And, as I pointed out earlier---even the biggest anti-apple sites are applauding Apple's efforts with this SoC effort.
    You're in the minority---and to be so vain that we would care about who you are and what your credentials are is silly. It sounds to me like you're a 17 year old with a decent vocabulary and not enough paper in the pocket to pick up an iPhone 5s for yourself. But...what do I know. I don't know you, your credentials...or how you lean politically, nor do I care.
    IMO---you're an insult to the entire Anand crew. I'm not sure why I continue to read your responses, they're all the same, just worded differently. Again...you're in the (extreme) minority. You're certainly not an engineer, chip designer, app developer or technological guru---if you were, you would understand the feat Apple has achieved with this SoC architecture.
    J
    Reply
  • Nurenthapa - Friday, September 20, 2013 - link

    I've been enjoying reading this in China, but you, sir, are really annoying me with your sniveling drivel. You have an axe to grind and simply won't shut up. Hope you disappear from this forum. BTW, I use a HTC One and iPad 2, and occasionally my old original 2007 iPhone. I love IOS and iPhones, but won't be buying one until they come out with a somewhat bigger screen. Reply
  • oryades - Wednesday, September 18, 2013 - link

    Intel, now Apple, the same featured reviews. Reply
  • edward kuebler - Wednesday, September 18, 2013 - link

    We are talking about 64 bits too much. The story is new instruction set in ARMv8. Instead complicating the hardware for backwards compatibility (e.g. look at x86 still supporting 16bit code) they wrote a new instruction set faster and less energy demanding. There is still ARMv7 compatibility, but the 64bit mode is independent. And the thing is, once you redesign your architecture, why not go 64bit? what´s the point of staying 32 bit? Moving more data is both slower and faster. More and wider registers help compiler optimizations and media decoding. I didn't get all this “cunning deceitful conspiracy” feeling you talk about. Staying in 32 bit land, *that* would keep me guessing. Reply
  • Anand Lal Shimpi - Wednesday, September 18, 2013 - link

    Our browser based suite (stressing js/HTML5 and other browser based workloads) remains unchanged from all of the other mobile SoC reviews we've done. There's no way of getting around the software differences on these mobile devices as you buy hardware+software together. Unfortunately it's still our best option for non-GPU cross platform comparisons, there just aren't many good cross platform CPU tests.

    I called out the inclusion of hardware accelerated AES/SHA when referencing those tests, there were no attempts to hide that fact. The fact remains that those algorithms will see a speedup on ARMv8 hardware because of those instructions. Note this is no different than when we run the TrueCrypt benchmarks on AES-NI enabled processors vs. those that don't have it (e.g. http://images.anandtech.com/graphs/graph5626/44765...

    Apple provided absolutely zero guidelines on how the review was to be conducted. The only stipulations were around making sure we didn't disclose the fact that we had devices. In fact, most manufacturers don't - at least not with us. Whenever there are any stipulations presented, we always disclose them on the site (e.g. see our early look at Trinity desktop performance).

    Krait implements ARMv7, so that's 64-bit wide registers for its NEON units. It expanded the width of the execution units, but the registers themselves have to adhere to the ARMv7 ISA.

    I think we explained why 64-bit makes sense (doing so at the last minute doesn't make sense, immediate SIMD/Crypto perf increases today, and helps build up the ecosystem), and even highlighted cases where a performance degradation does happen (see: Dijkstra tests). Keep in mind that iOS has always erred on the side of being more thrifty with RAM to begin with. I would like to see more but I don't know how necessary it is today.

    Take care,
    Anand
    Reply
  • ddriver - Wednesday, September 18, 2013 - link

    Anand, maybe you should hire a developer to write native cross platform benchmark tools. This is the only way to avoid all caveats like sponsored exclusive optimizations, different implementations, eliminate unrealistic low footprint synthetics, "selective compilers" (*cough Intel*) and whatnot. Considering the amount of reviews you are doing and the fact that C/C++ compilers have caught up with ARM for a long time, this is nothing hard and something that entirely makes sense, especially relative to using different JS engine implementations to measure CPU performance. JS should go in the "browser" department, not CPU performance.

    According to wikipedia, Krait implements 128bit SIMD, so maybe that is a mistake on wikipedia's behalf?

    I still think encryption results belong in their own chart, and have no place in a chart that is supposed to be indicative of the integer performance delta between 32 and 64bit execution modes. Even with the clarification you made, it creates an unrealistic impression, not to mention some people skimp over the text and only look at the numbers. Encryption is encryption, integer performance is integer performance. Why mix the two (except for the reason I already mentioned and you deny)?

    I wish you'd reflected a bit on the marketing aspect of the transition to 64, considering how much apple is riding it this time around. No one argues 64bit is good and more performance is good, but this brings up the issue of the particular implementation, e.g. a fast chip with only a single gigabyte of ram, and how will that play out with an actual performance demanding real world application.

    Thanks for addressing my concerns.
    Reply
  • Wilco1 - Wednesday, September 18, 2013 - link

    ARMv7 has 32 64-bit SIMD registers but they can also be used as 16 128-bit SIMD registers. Modern CPUs like Cortex-A15 and Krait support many 128-bit SIMD operations in a single cycle, but not all operations are supported (such as double precision FP). ARMv8 has 32 128-bit SIMD registers and supports SIMD of 2 64-bit doubles. Reply

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