Camera shootout: How the iPhone 6s compares to the iPhone 6

29.09.2015
If you glance through the iPhone 6s’s specs and list of features, you would be forgiven for thinking that its most important camera upgrade is the sensor on its back-facing camera, which has been bumped from 8 megapixels—which has persisted since the iPhone 4s—to 12 megapixels. Actually, the increase in resolution is the least interesting thing to happen to what is, remember, the most popular camera in the world. Far more exciting is what’s happened to the camera on the other side of the iPhone, and what Apple is doing with video.

To better understand the iPhone 6s’s photographic abilities, and to help you decide if you want to upgrade from its immediate predecessor, we ran some side-by-side tests of the iPhone 6 and 6s. These tests were—how shall we put this—appropriately scientific. That is, we shot with both iPhones at the same time, but we were taking real world photos, not artificial studio shots of grey cards and ISO testing charts. Also, while we’ll try to illustrate what we’re talking about with examples, the limitations of color and resolution of different monitors, not to mention weirdness that can happen on the web, means that you might just have to trust us on a few points.

Let’s get to it. (For more on the iPhone 6s and 6s Plus, check out our full review.)

First, that resolution. 12 megapixels rather than 8 is not nothin’—it’s a 50 percent increase in the number of pixels, after all—and having that extra detail captured with each shot gives you few more creative options in editing. You can adjust the crop, if only a little, to recompose the shot while retaining good levels of detail, but don’t think of it as giving you much in the way of zoom compared to an iPhone 4s or later. It’s the equivalent of taking a pace or two forward, but nothing more. 

Still, there is a problem with adding more pixels into a small sensor. While more pixels make up the image—and so in theory you get more detail—physics fights you, and each individual pixel does its job less well: You actually instead get messy, smudgy detail. This is a problem that Apple seems to have countered effectively with smart engineering. Indeed, the detail in well-lit shots is crisp, and colors are excellent.

It looks like Apple has also tweaked the image processing in the 6s compared to the 6—consistently, blacks were deeper and images showed greater clarity:

And again:

This is a tricky balance to get right. If a camera is too restrained in how it processes images, they’ll look flat and lifeless, but boost them too much and they’ll start to look silly and amateurish. Happily, Apple’s gentle tweaks here do seem to have struck the right balance: The images above show the extra punch the 6s’s photos have, but the subtlety of the tones in this Hydrangea’s petals are even more deftly rendered by the 6s compared to the 6. 

Thanks to these tweaks, the iPhone 6s demonstrates noticeably better dynamic range in its shots compared to the iPhone 6. The iPhone 6 is still a superb smartphone camera (and overall “a very good camera” if you remove the “smartphone” caveat), but look closely at this shot—which is a very tricky one to get right, with its brightness, shadows and fine detail—and you’ll see that the 6s fares better: 

Look closely at the point where the individual leaves join at the stem—see how the 6s manages to hold onto detail and subtlety in the bright areas of the leaf that the 6 is beginning to give up on Some might prefer the 6’s shot overall, but the 6s has captured more detail and nuance, and so you have the option of retaining it or blowing out the highlights a bit for a more in-your-face shot.

The back-facing camera’s performance in low light is slightly improved in the 6s over the 6, but there’s not much in it, and that’s entirely consistent with what’s happened to the sensor—that is, it had its resolution bumped, but intelligently and cleverly. Witness this shot at dusk, where I’ve deliberately had the iPhone boost the exposure above what it wanted to produce by tapping on the building on the left:

Look at how smudgy the detail is in the reflection under the lawn at the left in the shot from the iPhone 6 compared to the 6s, and note how generally better processed the 6s’s shot is overall—richer, less washed out.

Here, for comparison, is what both phones originally metered the scene as—the differences are minor between the two models, but they’re there. Look at the water at the far left of the frame to see how the 6s is picking up more detail:

Still, though, low light performance remains a good way behind a dedicated semi-serious digital camera, something with even an APS-C-sized sensor, never mind full-frame. Held one-handed, the iPhone 6s fares no better at getting this shot inside a dim church—note the camera shake.

You can do better with a firmer grip, and it’s likely the 6s Plus, with its optical image stabilization, would banish this slight motion blur, but it’s still worth remembering that good though the 6s’s camera is, it’s not especially hard to bump into its limitations.

One quick aside: HDR mode does a great job at adding apparent definition in some tough lighting conditions. Here’s the 6s dealing with one such composition normally, without HDR:

And here, with. See how the stonework in the middle of the frame doesn’t just add darkness, it seems to get sharper, too: 

For comparison, here’s the 6’s HDR shot. Again, pretty good, but see how much detail is lost in shadows towards the left of the frame: 

This dark church interior gives us a chance to switch our focus to the front-facing camera—the camera which has had a far bigger upgrade. Apple calls it the FaceTime HD camera, but to everyone else it’s the selfie camera, and it’s a testament to how popular the form has become that so much attention has been lavished here.

First, the resolution has been more than quadrupled, from 1.2 to 5 megapixels. But—sing it with us—that’s not really that big a deal in itself. More important is that the front-facing camera is no longer an impoverished relation of the back-facing camera, neutered of all the fancy features. Live Photos works on both, and you can now take HDR shots on the front camera as well. 

Plus, there’s even a flash, of sorts: The screen flashes—three times brighter than its usual max setting—when you hit the shutter, to help illuminate your grinning visage. Just as how the two-tone flash on the back-facing camera measures the ambient light quality to flash in a sympathetic color, so too does the screen adjust its hue. Let’s see how it all works. 

Here’s a selfie shot with the front camera of both iPhones, with the flash of the 6s suppressed:

Already, a huge improvement. But let’s turn on the flash—which will trigger the screen to blink brightly when I take the shot: 

So much better—in that you can see my face much more clearly—though perhaps a little full-on. You’ll see that I’ve removed my glasses—that’s because that big rectangle of light flashing can bounce off their lenses a bit distractingly, which is not ideal. 

If, however, I take the kind of selfie people actually take rather than one to test a camera, it all comes together and makes sense. 

While there is still vast room for improvement with this shot, the flash that seemed too bright at close quarters illuminates the scene pretty well, and provides pleasing catch-lights in my eyes. Compare it to the best the iPhone 6 can do, and you can see that for normal selfies—or at least, more normal selfies taken with friends in clubs rather than alone in small, deserted Norman-era churches—the 6s is a big upgrade.

And it’s not just in low light situations that the 6s’s hugely improved front-facing camera trounces the 6’s—but there is a caveat. Compare these two selfies, one taken with the 6, one with the 6s: 

It’s a sunny day, but the sun is currently behind a cloud, so the light is pretty scattered and flattering. Not only is the picture from the 6s less flat, but the increased resolution means that you can make out the fine pattern of the fabric of my jacket, say, instead of seeing the moiré pattern in the shot from the iPhone 6. 

And then here, in direct sunlight, just an overall more pleasant result from the 6s: 

Ah, but that caveat. Both the shots you see here from the iPhone 6s are with HDR turned on, which has used its combined multiple exposures to fill out blown highlights and darken up shadows. The results from the iPhone 6s’s selfie camera with HDR turned off, while they give you more options thanks to their higher resolution, are actually arguably less good than those from the iPhone 6 if you’re thinking in terms of small thumbnails shared for fun on social media. Here are those regular, non-HDR 6s shots for the two scenes above: 

A couple of other notable things: Panoramas are now even bigger, thanks to the 6s’s increased resolution—63 megapixels rather than the already-amusingly-huge 43 megapixels of the 6-series hardware. Despite this larger side, taking panoramas is still fast, presumably at least in part thanks to the 6s’s A9 processor. Indeed, if the selfie-in-a-church thing wasn’t bad enough, I looked quite, quite mad spinning around in its grounds trying to go too fast for the 6s to keep up. (It can be done, but that it’s so fast shows that in less artificial contexts the 6s will easily process panoramas quickly enough. Things slow down the darker it gets, mind.)

Burst mode, though, does suffer, presumably as a result of the 50-percent bump in resolution. Keeping the shutter depressed for about 10 seconds, the iPhone 6 shot 95 pictures, compared to 76 from the 6s. Let’s not get carried away: In most situations, the burst mode speed of the 6s is completely fine and should net you the shot you want, but it’s just worth noting that it’s around three-quarters the speed of the iPhone 6.

Of course, your other new option is Live Photos. With this turned on, your iPhone will capture 1.5 seconds of footage both before and after you press the shutter. (Well, I say footage, but Apple is at pains to point out that this isn’t video, even if what you import onto your Mac is, yes, technically, a .mov file.) 

Yes, this is complicated. You might have gotten it into your head that Live Photos are a series of full, 12 megapixel images, but Apple actually says “At the heart of a Live Photo is a beautiful 12-megapixel photo. But together with that photo are the moments just before and after it was taken, captured with movement and sound.”

In other words, the photo at the point you press the shutter is full-res, but not necessarily the footage you captured before and after, which you can see when you look at the imported .mov files—they’re 1440-by-1080, not 4032-by-3024. This helps explain why the .mov file that correlates to each JPEG is no more than twice its file size—and also, presumably, explains why you can’t define a different “poster frame” if you like, or save out different moments from the Live Photo as if it was a series of burst photos. 

Once shot, you can use 3D Touch to activate them (with audio), or set them as wallpaper on your iPhone or Apple Watch. Sharing them is messy at the moment, but should improve as developers use Apple’s specs to incorporate them into, say, Facebook. 

It’s a cute idea, and the examples on Apple’s website show exactly why it should work, but honestly, I’ve struggled to create anything half as compelling, and I speak as a man with an adorable two-month old daughter. Worse, perhaps, the frame-rate of Live Photos (14.99 fps according to QuickTime) is jarringly low, in stark contrast to the buttery-smooth interface throughout. Still, there is a magic to them: They remind me of the moving photos featured in Harry Potter—maybe in part because the low frame-rate somewhat evokes the flickering of ciné film. 

Still, I’m personally left a little nonplussed by Live Photos. The still/video thing just seems messy and unresolved, and if it’s just video-with-a-JPEG-in-the-middle, why is the frame-rate so low Surely there’s enough muscle Perhaps it can be improved with an iOS update, and I’ll certainly keep it around on my 128GB iPhone 6s for all the few extra megabytes it will cost me, just in case I do capture something I love. (16GB iPhone owners might want to think twice.) It might be that I just haven’t gotten my eye in yet for what makes a good Live Photo. 

Straight video is the other big upgrade with the 6s, since it can now shoot in 4K. 4K is four times the resolution of 1080p, also known as Full HD—think of a grid of four TVs stacked in a two-by-two grid—and so one of the big advantages of it is that you get more creative control in editing. Whereas the jump from 8 to 12 megapixels is a jump of only half as much again, going from 1080p to 4K is a fourfold increase in resolution, so you can do much more with cropping. In the video below, for example, the first five seconds show 1080p footage from the iPhone 6, while the last 10 show a 1080p-sized chunk cropped, cookie cutter-style, from the middle of some 4K footage off a 6s. 

In other words, if you intend to output at HD rather than 4K, you do get a facsimile of a zoom lens with the iPhone 6s by shooting in 4K, and you have the option of recomposing footage after it’s shot without it starting to look blocky and low-res. 

Of course, you could instead target 4K output, and the native 4K footage from the 6s is good. It’s not jaw-dropping—certainly, nothing like the quality from a Canon EOS-1D C or RED camera, even before you start talking about the creative possibilities from different lenses those cameras have—but essentially like the video footage you’d get from an iPhone 6, just with much more detail. If you have a monitor or TV that can display at least 4K, it will look impressive, though if you’re just shooting fun little videos to share on Twitter, rather than raw footage for projects or for posterity, it’s (at least currently) overkill. 

Here’s a quick example, though you’ll need to be using a display capable of at least 4K to see the difference. (Note: We’ve found YouTube’s handling of 4K video to be a little finicky. For best results, try viewing this video in Firefox.):

The 6s also adds the option of shooting 120 fps slow-motion at 1080p (as well as 720p at 240 fps) rather than both 120 and 240 fps options being limited to 720p as on the iPhone 6. That’s great, but we’d have loved something slower still as well, even if limited to 720p.

One last thing semi-related to video: Time-lapse “photos” (which are really videos, both technically in the way they get recorded as well as visually) are now stabilized. This is actually done in software on the iPhone 6s and 6s Plus (and so is unrelated to and independent of the optical image stabilization system in the iPhone 6/6 Plus), and so I wondered if it has been rolled out to all iOS 9-compatible devices. According to Apple, the answer is no—but it does at least work on the 6 and 6 Plus, too.

The results are good—better than not having it—though Hyperlapse still does a better job, both of stabilization and managing the exposure. In this example, the iPhone is being held in one hand as I walk, and a good deal of the bounciness has been suppressed:

You can’t take a photo from a standing start appreciably faster with a 6s compared to a 6, at least so far as the hardware is concerned, but there is a wrinkle. Touch ID is now so fast that your muscle memory has you shooting past the lock screen so unthinkingly quickly that there’s usually no opportunity to flick up the camera icon at the bottom right. But if, like me, you banished the Camera app from your first Home screen when that swipe-up was added, bring it back if you get a 6s, since pressing firmly on it offers you the option of launching it directly already into selfie, video, slow-mo, or regular photo mode. In other words, while you at first curse the newly fast Touch ID, missing the option of flicking up on the lock screen to quickly launch your camera, actually, quickly unlocking your phone and using 3D Touch to launch the camera in the mode you actually want to use saves on mucking about once the camera is launched, and so the effect is that in many cases the 6s is faster to first shot than the 6. 

So after three thousand words, what have we learned Basically, that photos taken with the iPhone 6’s back-facing camera are very good, that photos taken with the iPhone 6s’s back-facing camera are better in small but significant ways, and that the best camera feature has nothing to do with photos at all—it’s all about 4K. The ability to shoot reasonably good 4K video gives filmmakers more creative options and gives the rest of us the opportunity to record home movies that our children might just conceivably refrain from saying look horribly fuzzy and old-fashioned. And, like it or not, the biggest improvement of all is with the front-facing “selfie” camera, which is now capable of better shots and now sports all of the fancy features that were previously limited to the main, back-facing camera. 

And, speaking personally, I’ve also learned that I might not be allowed back into the grounds of St Mary’s Charlcombe in Bath.

(www.macworld.com)

Christopher Phin