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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  • ddriver - Wednesday, September 18, 2013 - link

    My basis for this conclusion is how the article is structured, the carefully picking of benchmarks and selective comparisons. This is clearly visible and has nothing to do with the actual chip specifications. It has nothing to do with execution mode specific details. So no, I don't have problem with facts, unlike you.

    Furthermore, that 30% number you were focused on is hardly impressive and proportional to the claims this article is making. In a workload that would take an hour, 30% is a noticeable improvement, but for typical phone applications this is not the case.
    Reply
  • Dooderoo - Wednesday, September 18, 2013 - link

    The structure of the article and the benchmarks are mostly the same as they use in most reviews, excluding some Android specific benchmarks. Where exactly do you see "carefully picking of benchmarks and selective comparisons". Put differently: what benchmarks should they include to convince you there is no "cunning deceit" at work?

    What claims in the article are not proportional with the 30% (actually more) performance gain?

    I won't even comment on the "not a noticeable improvement" bit.
    Reply
  • andrewaggb - Wednesday, September 18, 2013 - link

    My issue with all the benchmarks is that they are mostly synthetic. The most meaningful benchmarks are the applications you plan to use and the usage patterns you are targeting. Synthetics are fascinating, but I think it's generally a mistake to buy anything based on them. Reply
  • notddriver - Thursday, September 19, 2013 - link

    Um, so if a 30% improvement is hardly impressive and irrelevant to phones, then isn't the entire concept of reviewing phones on the basis of hardware performance also irrelevant? Which would make your complaints about the biased-yet-insignificant-review as vital as a debate over whether Harry Potter or Spiderman would be better at defending Metropolis.

    Incidentally, my iPhone 5 is powerful enough that I never notice any issues—as I'm sure the last generation of Android phones would be. But if your going to go to town over a dozen or more comments about a topic, at least pretend that it matters a tiny bit. Just good form.
    Reply
  • oRdchaos - Wednesday, September 18, 2013 - link

    I've seen people all over the web get very worked up about people's phrasing with regard to 64-bit. Would you prefer the title of the section were "Performance gains from a 64-bit architecture and the new ARMv8 instruction set"? People keep arguing that 64-bit in a vacuum doesn't give much performance gain. But there is no vacuum.

    I think the article is very clear to point out where gains are from additional instructions, versus a doubling of the register bit width, versus improved memory subsystem/cache. I'm sure when they get chances to write more of their own tests, they'll be able to pinpoint things further.
    Reply
  • sfaerew - Wednesday, September 18, 2013 - link

    engadget is multi-thread geekbench performance. tegra4 4cores vs A7 2cores Reply
  • Spoony - Wednesday, September 18, 2013 - link

    - You are correct, there are no native cross-platform benches used. Which ones do you suggest Anandtech use? We all know Geekbench is essentially meaningless across platforms.

    - If you are talking about this engadget review: http://www.engadget.com/2013/09/17/iphone-5s-revie... It appears that Nvidia SHIELD (Tegra 4) led in only one benchmark out of six. This makes your statement incorrect. LG G2 is more competitive. Need we repeat how inaccurate Geekbench is cross-platform. It is as apples-to-oranges as the JS tests.

    - I believe what Anandtech was attempting to show with the encryption was the difference ARMv8 ISA makes. In fact the title of that somewhat sensational chart is "AArch64 vs. AArch32 Performance Comparison". So while you are right, the encryption tests are handled in a fundamentally different way, that way is part of the ISA and is an advantage of AArch64, and thus is valid in the chart.

    - It will be curious to see whether Qualcomm can deliver A7 like performance using ARMv7 with extended features. My position is no, which is the whole point of that entire page of the review. ARMv8 is actually enabling some additional performance due to ISA efficiency and more features.

    - I think noticeable memory footprint bloat of a 64-bit executable is completely ridiculous. But to see if I was right, I did some testing. It's getting a bit hard to find fat binaries to take apart these days, most things are x86_64 only. But I found a few. I computed for three separate applications, took the average, and it looks like about a 9% increase in executable size. Considering that executables themselves are a tiny part of any application's assets, I think it is completely insubstantial. If you calculate the increase in executable size versus the size of the whole application package, it averages to a less than 1% increase.

    I too am a bit sad that Apple didn't increase the RAM, and also equally sad that connectivity was left out this rev. I continue to be sad that there is not a more serious storage controller inside the phone. You make some valid points, but I think you also make some erroneous ones. The question with phone SoCs is: Is this a well balanced platform along the axes of performance (GPU and CPU), power consumption (thus heat), and features. I believe that the A7 is well calibrated. Obviously Qualcomm is also doing great work, and perhaps their SoCs are equally as well calibrated.
    Reply
  • ddriver - Wednesday, September 18, 2013 - link

    - This is entirely his decision, considering writing those reviews is his job, not mine. He can either use actual native benchmarks which reflect the performance of the actual hardware, or call it JS VM performance instead of CPU performance, because different JS implementations across platforms are entirely meaningless.

    - there is only one geekbench test at engadged. That is what I said "geekbench" - I did not imply it was faster in all tests in the engadged review, I don't know why you insinuate I did so. IIRC snapdragon 800 is actually a little slower in the CPU department than tegra 4, and only faster in the graphics department.

    - the boost in encryption is completely disproportional to other improvements and is due to hardware implementations, not 64bit execution mode. So, if anything, it should be a graph or chart on its own, instead of using it to bulk up the chart that is supposed to be indicative of integer performance improvements in 64bit mode.

    - maybe v7 chips with 128 bit SIMD units will not deliver quite the performance of A7, because there is more to the subject than the width of the registers (the number of registers doesn't really matter that much), like supported instructions. At any rate, v7 chips are still quad core, which means 4x128bit SIMD units compared to the 2 on A7, albeit with a few extra supported instructions. Until any native benchmark that guarantees saturation of SIMD units pops out, it will be a foolish thing to make a concrete statement on the subject. But boosting v7 SIMD units to 128bit width will at least make it competitive in number crunching scenarios, which use SIMD 99% of the time.

    - this is very relative, you can store the same data in three different containers and get a completely different footprint - a vector will only use a single pointer, since it is continuous in memory, a forward list will use a pointer for every data element, a linked list will use two. Depending on the requirements, you may need faster arbitrary inserts and deletions, which will require a linked list, and in the case of a single byte datatype, a 32bit single element will be 12 bytes because of padding and alignment, while in 64bit mode the size will grow to 24 bytes, which is exactly double. Granted, this is the other extremity of the "less than 1%" you came up with, truth is results will vary in between depending on the workload.

    As I said in the first post, the wise thing would be to reserve judgement until mass availability, mostly because I know corporate practices involving exclusive reviews prior to availability, which are a pronounced determining factor to the initial rate of sales. In short, apple is in the position to be greatly rewarded for imposing some cheating requirements on early exclusive reviewers. And at least in this aspect I think everyone will disagree, apple is not the kind of company to let such an opportunity go to waste.
    Reply
  • ddriver - Wednesday, September 18, 2013 - link

    *no one will disagree Reply
  • Dug - Wednesday, September 18, 2013 - link

    I will.
    "As I said in the first post, the wise thing would be to reserve judgement until mass availability, mostly because I know corporate practices involving exclusive reviews prior to availability, which are a pronounced determining factor to the initial rate of sales. In short, apple is in the position to be greatly rewarded for imposing some cheating requirements on early exclusive reviewers. And at least in this aspect I think everyone will disagree, apple is not the kind of company to let such an opportunity go to waste."

    Prove it and stop making assumptions.
    Reply

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