Quick Review: Apple iPhone 5 Camera
Barney Britton, Kelcey Smith | Product Reviews & Previews | Published Oct 1, 2012
Apple might not have set out to make some of the most popular cameras on the planet with its iPhone range of smartphones, but that's exactly what has happened. The evolution of the iPhone cameras has been interesting to watch, from the 2MP mediocrity of the original iPhone and iPhone 3G, to the more serious 5MP iPhone 4, and the genuinely very nice 8MP resolution of the iPhone 4S.
The iPhone 5, Apple's latest model (actually the sixth iPhone, but anyway...) brings a larger screen, faster processor and redesigned camera compared to its predecessor. The pixel count is unchanged though, at 8MP. On paper, the iPhone 5's camera offers very similar specifications to that of the iPhone 4S, but according to Apple, the new model should give superior results. In this short article we're going to take a look at how the iPhone 5 stacks up aginst the iPhone 4 and 4S. We're working on a more in-depth test, which will compare the iPhone 5 against competitive smartphones, and that should be ready in a few days.
Studio Scene (indoors, artificial light)
Inevitably, the lack of white balance and ISO control means that our comparison images vary a little in exposure and color. The iPhone 4S, especially, delivers a noticeably warmer rendition in comparison to the other models. In the bright lighting of our studio, all three cameras selected their base ISO sensitivity settings - ISO 50 for the iPhone 5 and 4S and ISO 80 for the iPhone 4.
Exposure and white balance was (by necessity) automatic on all three phones.
|iPhone 5 (100% Crop)||100% Crop|
|iPhone 4S (100% Crop)||100% Crop|
|iPhone 4 (100% Crop)||100% Crop|
At first glance there doesn't seem to be much appreciable difference between the 4s and the 5 except for a slight variation in sharpness and contrast. Both however, are significantly more detailed due to a 60% increase in pixel count over the iPhone 4.
Compared to the iPhone 4S, the iPhone 5's output is slightly smoother, and this 'softness' has been widely discussed since the phone was released. But close examination reveals that while images from the 5 may be perceptually slightly softer, detail capture is virtually identical to images from the iPhone 4S.
The slight difference in the look of the images is almost certainly due to tweaked noise reduction in the iPhone 5, which seems to be reducing the 'grit' of luminance noise more effectively, coupled with a different approach to sharpening. It certainly seems like the iPhone 5 applies noise reduction and possibly also sharpening selectively, depending on the scene content. Midtones are kept nice and smooth, thanks to relatively aggressive luminance noise reduction, but contrasty, detailed areas are grittier and sharper.
In good light each of the cameras has, as we'd expect, chosen its lowest ISO (50 for the 5 and 4s, 80 for the 4). All three iPhones have metered this scene well and saturation is fairly natural and pleasing. The iPhone 4 is noticeably more saturated than the other two and the higher contrast makes images look more 'punchy' alongside the same shots from the iPhone 5 and 4S.
As far as detail capture is concerned, there's not much to choose between the three phones, and certainly not between the 4S and 5. The iPhone 4's files are slightly smaller, obviously, but in the favorable conditions of a sunny day, it's done well here, despite the smaller pixel count. If you look very closely though you should be able to see that the 5MP iPhone 4 can't quite render the small text on the lifebelt in the left-most crop, above.
Turning our attention to the plain blue sky, all three cameras show moderate luminance noise but close inspection reveals that as we suspected, the iPhone 5 is applying more aggressive smoothing. The difference is subtle but there is a difference. In general, adaptive noise-reduction is a good thing - smooth the areas that can safely be smoothed (areas of plain tone) and leave the luminance 'grit' in the areas where noise reduction might compromise resolution (areas of fine detail). We've seen it work well on some recent compact cameras, and it seems very likely that Apple is using the same principle here.
Apple claims that the iPhone 5 offers improved low-light performance compared to the 4S. It certainly offers a more twilight-friendly ISO span, up to ISO 3200, compared to a maximum of ISO 1000 in the 4S. Let's take a detailed look.
The camera modules of the 4S and 5 are different, but it seems likely that they're based on similar underlying hardware. The iPhone 5 is certainly applying more noise-reduction to areas of plain tone than the 4S, but up to ISO 1600, there's very little difference between the two cameras.
The iPhone 5's trump card in poor light, compared to the 4S, is its additional ISO sensitivity span, which goes up to ISO 3200 (automatically - you can't control ISO manually). To get the iPhone 5 to shoot at its very highest ISO sensitivity settings, the light has to be extremely low. For the examples below, we moved our single tungsten light progressively further away from our still life, decreasing the amount of light falling on the scene.
|iPhone 5, ISO 800||100% Crop|
|iPhone 5, ISO 2000||100% Crop|
|iPhone 5, ISO 3200||100% Crop|
Well, there we have it. The iPhone 5's sensor isn't magically more sensitive than its predecessor after all. There have been rumors of pixel-binning and multi-shot noise reduction at play in the iPhone 5, and based on what we've seen, it does look like the iPhone 5 employs some sort of pixel-binning at its highest ISO sensitivities, and upsizes the resulting images to 3264x2448 pixels (8MP). Notice how sharpness drops significantly between ISO 800 and ISO 2000. This appears to be more than just increased noise and more aggressive noise-reduction.
Try as we might, we couldn't get the iPhone 5 to select ISO 1600 when capturing this scene, but in supplemental shooting we've established that the switch occurs between ISO 1000 and ISO 1250. Images captured at ISO 1000 are noisy but sharp, and images at ISO 1250 and above are smoother, brighter, but much less detailed, suggesting a loss of true resolution (rather than just a masking of detail, caused by noise and NR).
This isn't a bad thing though. Although we'd love DSLR-level high ISO performance in a cameraphone, it's an unrealistic expectation. By combining the signals of neighboring photosites in this way, the iPhone can capture images in light much lower than its predecessor the iPhone 4S, and the drop in pixel-level image quality will probably be unnoticeable when the images are used for social and web use.
Interestingly, right now this 'boost' mode is not available when running third-party camera applications on the iPhone 5. But according to a recent report, app developers will have the option of activating it if they desire, and it is likely that the next round of updates to popular apps like Camera+ and Instagram will be able to take advantage of the new high-sensitivity mode in the near future.
Camera phones are not well known for their flash capability. Some have real xenon flash strobes, but most are nothing more than a very bright LED. The iPhone 4, 4S and 5 all feature LED flashes, and while none can match the flashes of even cheap compact cameras for output power, they can come in handy for close-range social portraits.
Looking at the crops of our subject's eye it is easy to see the affect of the iPhone 5's more aggressive noise reduction. The eyebrows and lashes are ever so slightly less well defined. Red eye is something that plagues all 3 cameras equally and in the default Apple camera app there is no option for red eye reduction. There is however a fairly decent red eye removal function available via the Edit options dialog on the iPhone.
For both the iPhone 5 and 4s the camera chose an ISO setting of 80. However the 4 chose a much higher ISO of 250 while keeping the same shutter speed as the other 2 cameras (~1/15s) which has resulted in a brighter image for the iPhone 4. As a consequence, the iPhone 4 has given a noisier image, but the moderate grittiness is not objectionable.
Only a few days after the iPhone 5 became available, people began reporting an issue with a mysterious 'purple haze' appearing in photos taken with a bright light source just outside of the frame. There has been a lot of speculation to what may be causing this phenomenon. Some theories revolve around sensor blooming and chromatic abberation, some speculation centers on the new sapphire glass element in front of the lens.
|iPhone 5 - (Outdoors - mid-day sun)||iPhone 4S - (Outdoors - mid-day sun)|
|iPhone 5 - (Studio, artificial light)||iPhone 4S - (Studio, artificial light)|
The so-called 'purple haze' issue is most obvious when the adjacent area to the flare is quite dark, which is a scenario that is actually quite common in low light situations where you may have a single bright lamp in an otherwise dark room. It can also be triggered by shooting towords the sun, or with any particularly bright light source at or just beyond the edge of the frame. So what's causing it? Here are some of the various explanations we've seen bandied around online.
Is it sensor blooming?
No. Blooming happens when the intensity of the light reaching the sensor is so great that there is an overflow of electrons that spill over into adjcent pixels. This is not a satisfactory explanation for the iPhone 5's purple haze, since sensor blooming affects the entire imaging field, meaning that you'd see it associated with a bright highlight positioned anywhere in the image, not just towards the edges of the frame, as we're seeing in pictures from the iPhone 5.
Look at the bright light at the top of the frame in this picture (not taken on an iPhone) - that's blooming.
Blooming is sometimes accompanied by vertical or horizontal purple lines, caused by electrons cascading between pixels during read out. Cameras with CCD sensors are more prone to blooming (the camera in this example is CCD) than the CMOS sensors found in the iPhone 4S and 5, and you're more likely to see it in video footage than stills.
Is it chromatic abberation?
No, definitely not. Typically visible towards the edges of the frame especially in images taken using wideangle lenses, CA takes the appearance of a green-and-magenta or blue-and-yellow 'fringing' around peripheral scene elements. It looks nothing like the iPhone 5's purple haze.
Is it because the iPhone 5's sensor is really sensitive to infrared light, like the Leica M8?
No, it isn't. This is one of the more outlandish suggestions that we've seen proposed, but still...
Long-time readers of this site will remember that the Leica M8's sensor was exceptionally sensitive to IR light which among other consequences meant that it had a nasty habit of turning black man-made fabrics purple. Leica ultimately 'fixed' the issue by sending M8 owners screw-in IR filters to attach to their lenses.
Is it internal reflections / Lens flare?
Almost certainly, yes. The most likely cause of the iPhone 5's purple haze is probably lens flare and internal reflections in the camera lens assembly. All lenses are succeptable to lens flare to some degree, and as you can see from the images at the top of this page, the iPhone 4S isn't immune either (ditto the iPhone 4 and competitive smartphones from other manufacturers).
But in our shooting we've found that it's a little more noticeable on the iPhone 5. So why is that? It's unlikely that the flare is solely due to the much-vaunted inclusion of a sapphire glass lens cover (although the refractive index of the sapphire glass is different to conventional optical glass, so it could be a contributing factor). Our money is on it being caused by a combination of different things, none of which, alone, is unique to the iPhone 5.
The primary way that lens manufacturers prevent lens flare is to coat the glass elements in an anti-reflective coating. The iPhone 5's lens elements are coated, but we don't know if the coatings are identical to those used in the iPhone 4S's lens. Maybe the sapphire glass has to be coated differently - we don't know. And we won't know, unless Apple releases a more in-depth statement about the technology.
Really, our advice is not to worry. Just do what you should do anyway, and avoid putting bright lights near the edge of the frame when shooting.
Along with stills image capture, the iPhone 5's video capability remains largely unchanged from the 4S. Thankfully this means that you can expect videos with good detail, motion and color saturation from the iPhone 5. Using the built in video camera is exactly the same as it was in previous generations. There's not much control available, only start and stop. However, Apple has added a nice feature to the iPhone 5 that allows you to capture an HD resolution (1920x1080px) still frame while continuing to shoot video. This is not a standard iOS 6 feature, and is unavailable on earlier generation iPhones.
Video sample 1
By default, exposure and focus are automatic in video mode but if you long-press the screen you can lock AF/AE on that point. To give you an idea of how the iPhone 5's exposure and AF operate when left to their own devices, take a look at this video. If you look closely at the sky, you will see that its brightness changes fractionally during the clip. This is almost caused by the phone's metering system trying to compensate for the bright white boat moving in and out of the iPhone's metering area, changing the tonal balance of the scene.
Video sample 2
The iPhone 5 is capable of capturing high quality 1080p HD video that rivals most current compact cameras. The videos are sharp and well detailed with a good level of saturation and contrast. Even though the iPhone 5's CMOS sensor is succeptable to the same 'rolling shutter' problems of its predecessors, it's not terribly obvious, as you can see (or not) in this hand-held panning shot.
As we mentioned in the introduction to this article, the iPhone in its various iterations, has become (quite unexpectedly) one of the most popular digital cameras ever invented. We've come a long way since the craptacular 2MP obscuroscopes offered by the early models, to the point where the iPhone 4S and iPhone 5 actually offer genuinely useful image quality that in favourable conditions, is hard to tell apart from the output from 'proper' cameras.
This is great news for people like us who write about digital photography, because it signals a paradigm shift. This doesn't happen often, and it's very exciting when it does. Already, we're seeing mainstream camera manufacturers scrabbling to add connectivity to their products, and it's not just desperation that's making them do it. If the iPhone, and devices like it, have had a transformative effect on the industry it's because they've had a transformative effect on peoples' expectations of cameras, and photography. And the industry is doing what it always does - moving to fulfill a need.
The iPhone 5 is a fine mobile device, with an excellent camera. In qualititative terms it's not the best camera out there, and nor is it the best camera on a smartphone (the Nokia 808 has that honor, for now) but it offers satisfying image quality, some neat functions like auto panorama and HDR mode, and - crucially - it is supremely easy to use. It isn't much better than the iPhone 4S, as far as its photographic performance is concerned, but it isn't any worse (notwithstanding a somewhat more noticeable propensity towards lens flare). When manufacturers employ pixel-binning to achieve higher ISO settings we don't normally celebrate the fact, but in the case of the iPhone 5, it gives you greater flexibility in poor light (i.e., you might actually get a picture now, where you just wouldn't with the iPhone 4S) and the drop in quality is unnoticeable when the images are used for sharing/web display.
We'll be taking more pictures with the iPhone 5, and doing more testing in the coming weeks. Until then, we hope you enjoy this gallery of real-world samples.
Real-world Sample Images
There are 35 images in our Apple iPhone 5 samples gallery. Please do not reproduce any of these images on a website or any newsletter / magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review), we do so in good faith, please don't abuse it.
Unless otherwise noted images taken with no particular settings at full resolution. A reduced size image (within 1024 x 1024 bounds) is provided to be more easily viewed in your browser. As always the original untouched image is available by clicking on this reduced image.
|Apple iPhone 5 Review Samples - published Oct 1, 2012|