Apple iPhone 6S review

Apple's 'S' model phones may look like their predecessors, but they generally get a internal revamp, adding new features and a faster processor. This time around, the iPhone 6S adds a considerable amount to the iPhone 6 with a higher-resolution camera and 3D Touch screen technology. Of course, what the specs don't tell you is if the updates are enough to make this the must-have phone; my review will reveal all.

Build quality

From the outside, very little has changed. The 6S is a fraction fatter and heavier than its predecessor, measuring 7.1mm thick and weighing 143g compared to the iPhone 6's 129g, 6.9mm chassis, but it's all pretty negligible once you've got them both in your hand. Of course, the iPhone 6S is meant to be much more durable this time round, as Apple says its chassis is now made from 7,000 series aluminium while its new glass panel uses a special ion-exchange process to help make it less susceptible to cracks and scratches.

Such claims are hard to prove without long-term testing, of course, but to the touch it's very much business as usual. The glass is just as smooth under your thumb as before, and the smooth, curved chassis feels solid. Its looks are a matter of preference: compared to its Android competition, I also find its design a little plain, particularly when you put it alongside the gorgeous Samsung Galaxy S6 Edge, for instance; other people love its simple looks. Whether you love it or hate it, you can't argue that it's exceptionally well made, though.

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Display

Another carry-over from the iPhone 6 is its 4.7in, 1,134x750 display. Again, not much has changed on this front, as it's still just as bright at 541.75cd/m2 and blacks are equally deep at 0.35cd/m2. Colour accuracy's slipped a bit down to 93.3% of the sRGB colour gamut, but the iPhone 6S still has very even coverage across the gamut.

Reds and magentas are slightly lacking, but it's still a beautiful-looking display that can easily sit alongside most other Android flagships. In my eyes, the Sony Xperia Z5 has the edge when it comes to best LCD panel, as its colours are just that bit richer, but the iPhone 6S certainly puts up a good fight. Likewise, with a contrast ratio of 1,542:1, there's plenty of detail on show and viewing angles are superb. In other words, there's nothing to really complain about here and the quality of the iPhone 6S' display is very good. The one thing that I would like to see is a little more resolution, with higher-resolution phones with this screen size looking that bit sharper.

3D Touch

One of the iPhone 6S's biggest features is 3D Touch. It's the mobile equivalent of Apple's Force Touch technology found in the Apple Watch and new Macbook, allowing you to press a little bit harder on the screen to access additional features, such as shortcuts from the home screen, preview emails and more.

It's the first time this kind of screen technology has made it into a handset and, in some cases, it's a genuine time-saver, as being able to jump straight to video mode on the camera or send a new message on Twitter without having to navigate to the respective menu in the app itself, for example, feels pretty smart and practical. There are still a lot of third-party apps which it doesn't work with, though, including Facebook, Spotify, Netflix, Amazon Kindle and Dropbox, for instance, but this will change over time, as the iPhone is so popular. The haptic feedback it provides is also excellent, as you get a small, single buzz when you press the screen correctly, and a triple vibration when the app doesn't support it; it really lets you know 'right' from 'wrong'.

^ Press a little harder on the screen and 3D Touch will allow certain apps to give you additional options you can tap 

In-app, 3D Touch supports up to two levels of pressure for Peek and Pop. For example, in the Mail app you can press hard to Peek at an email and view a bit more of its contents, to see if you want to read the entire thing; press down again and you Pop into the mail to edit it normally. How useful this is depends largely on the type of mail: you can't see much of a marketing email that has a large image in it, for example. It's arguably more useful in the Camera app, where you can Peek at the preview photo to make sure that you've captured a decent picture; if you decide to do a bit of editing, you can Pop into the editor to make your changes. 

It can feel a little strange using 3D Touch, as the natural instinct is to press once and then press harder to follow up; one smooth motion works much better, with the phone very responsive and quick to respond. 3D Touch can also bring up the task switcher if you press on the left-hand side of the screen. I found it easier to just double-tap the home button; arguably, it's a feature better suited to larger iPhone 6S Plus, where it's hard to tap the home button when you're holding it one-handed.

Once you get used to 3D Touch and the way it works, it adds an extra dimension to the way that you interact with your phone and is a geniune improvement over the touchscreen in the iPhone 6. It may not prove enough of a draw to make people upgrade from the previous generation handset, but 3D Touch is certainly an improvement in phone interfaces and we're bound to see more from it as the technology matures and more developers support it.

Camera

Apple has upgraded the camera to use a 12-megapixel sensor, rather than the old 6's 8-megapixel model. Of course, the big difference is that you get more resolution, which means a little more detail in images. Exposure control is pretty similar to that of the iPhone 6, which isn't a huge problem as that phone generally picked the right automatic settings to capture a scene.

Testing the phone outside, I found that test shots were generally very good. Leaving the phone on its Auto HDR mode, I found that it managed to capture challenging shots, such as the contrast between the dark streets and bright sky in the photo below, pretty well. When compared to its nearest competition, the Galaxy S6, Samsung's phone produced truer colours and its higher-resolution sensor captured more detail; in comparison, the iPhone 6S, seems to process the image more, sharpening the picture. You could say that the S6's image is more true to life, while the iPhone 6S produces a slightly hyper-real version; I slightly prefer the S6's photos here.

When there's less dynamic range in the photo, such as capturing an image on a bright sunny day, the iPhone 6S does a brilliant job, as you can see from the test shot below. This photo is clean with realisitic colours, capturing the full detail in the image. On the whole, there was very little noise and I was generally quite pleased with each individual shot.

^ In brighter weather, the iPhone 6S produced great pictures

Photos in-doors are really rather good. Comparing the iPhone 6S to the Galaxy S6, I found that the iPhone produced a better-exposed photo and its auto white balance feature naturally found the right setting; Samsung's camera tended to make the image a little too warm. Samsung also uses some rather aggressive noise reduction methods, which tend to blur out some of the finer details. While the iPhone 6S has a little more image noise (but it's shots are far from noisy), it retains the finer detail, as you can see from my still life shot below, with the texture on the teddy bear's fur. In short, the Galaxy S6 produces better photos outside, but the iPhone 6S is better indoors. Both have great cameras.

If it gets too dark to take photos, the iPhone 6S has the true-tone flash, which uses dual-LEDs to match the scene's ambient light. The results are impressive, with bright photos that don't look as though they were taken with a flash. This year, the new 5-megapixel FaceTime camera on the front can use Retina flash, which lets the screen flare up to match ambient light levels and act as a flash for perfect selfies. It works surprisingly well and is great if you're trying to take a shot in a dark room.

Live photos

Live photos is a new mode, which records 1.5 seconds of video before you take a photo and 1.5 seconds afterwards. When you use 3D Touch to press on a photo, the video kicks into life, giving you some context (and sound) around the final photo. Getting the perfect live photo isn't always easy. If you move the phone too quickly before or after taking a photo, for example, you just capture a blur as the camera moves away from your subject. Fortunately, it's easy to remove the live part from a photo, using the Edit button, leaving you with the photo you want and getting rid of the video you don't. When Live photo works well, though, it's a great addition to the iPhone, with the added video prompting memories of the context the photo was taken in.

New video modes

The higher resolution video means that you can now shoot 4K video at 30fps. By default the phone is set to record 1080p video at 30fps, but you can change to the 4K mode by going to Settings -> Photos & Camera. In this mode, you'll get more detailed video: the iPhone's screen can't display video at full resolution, but you can watch it on another device or use pinch-to-zoom to get more detail. Once a video's on your computer, you can even grab an 8-megapixel frame out of the footage and save it as an 8-megapixel shot. While 4K video may not be that useful to most people, the new 1080p 60fps mode will be. This is twice the frame-rate of previous phones, which means for smoother action, particularly if you're shooting anything fast-moving, such as sports. When shooting any video, you can tap the shutter button to take an 8-megapixel photo.

Slow motion has also been improved, and you can now shoot 240fps at 720p (as with the iPhone 6) and, new to the iPhone 6S Plus, 120fps at 1080p. It's great fun using slow motion and the choice between modes really comes down to whether you want more detail or slower images: for me, 120fps and 1080p is the right mode for most situations.

Performance

One thing I can't fault, though, is the 6S's performance. iOS 9 feels super slick with Apple's new dual-core 1.8GHz A9 chip and 2GB of RAM behind it, and it delivers a substantial performance boost over the iPhone 6. For instance, whereas the iPhone 6 scored just 2,877 in the multicore test of Geekbench 3, which is still highly respectable, the iPhone 6S almost doubles that to 4,417. There's a similar leap in Geekbench 3's single core test as well, with the iPhone 6S leading the pack with 2,532 compared to the iPhone 6's 1,601.

It's not quite the fastest phone around, though, as the Samsung's Galaxy S6 family edge ahead on the Geekbench leaderboard with a comfortable lead of around 500 points; however, this needs four cores to do this and it lags behind in the single-core test. Still, the iPhone 6S has more than enough speed and power to run iOS 9, with the operating system super smooth.

Likewise, web performance was exceptional. iPhones have always been much more efficient web browsers than Android phones, but the iPhone 6S's massive Peacekeeper score of 4,568 only widens the gap further. The fastest score I've seen on an Android phone, for instance, is the Sony Xperia Z5 Compact's 1,629, which pales in comparison. While still perfectly quick on Android, the iPhone 6S is in another class entirely, with silky smooth scrolling no matter what type of web page is being rendered.

Likewise, iPhone 6S is an unparalleled mobile gaming device, with scores of 2,474 in the offscreen Manhattan test of GFX Bench GL and 3,414 in the onscreen test. These equate to roughly 40fps and 55fps respectively, putting it streets ahead of its Android rivals. Again, the Xperia Z5 Compact comes closest with its offscreen score of 1,545, but this only works out to around 25fps, making the iPhone 6S twice as quick when handling complex games. As a result, I had no problem at all playing games like Hearthstone or Asphalt 8, so you should find it more than capable of playing anything you want that's currently available in the App Store.

Battery Life

Unfortunately, all this power does come at the cost of the iPhone 6S's battery life, as it only managed a fairly average 11h 18m in our continuous video playback test when the screen brightness was set to 170cd/m2. The iPhone 6, on the other hand, lasted almost two hours more under the same conditions, making the 6S less reliable over the course of a day. This is still perfectly acceptable for a 2015 flagship, but this, together with the rest of the 6S's mediocre upgrades, make a bit of a deal breaker, especially if you're already underwhelmed with your iPhone's current battery life.

Conclusion

You have to look at a smartphone as an overall package, with it being the sum of its parts. Taken like this, the iPhone 6S remains a great smartphone: it's staggeringly quick, it's camera is very good and iOS 9 is a brilliant and slick operating system. That said, there are a few little niggles with this version: reduced battery life is a little annoying, while the screen is starting to feel a bit low-res. With that in mind, anyone with an iPhone 6 won't find this phone a worthy upgrade, although those with an iPhone 5S or older will. Even so, as an overall package, the larger iPhone 6S Plus now feels like it's the best choice, moving up in Expert Reviews' estimations as the high-end phone to buy. If you're looking for something else, our best smartphone guide will have a mobile phone that suits your needs.