iPhone 5s review

Adding an S to the previous year's new-shape iPhone is a pattern we've seen before, ever since the iPhone 3G turned 3GS in 2009. And once again in 2013 Apple evolved its existing iPhone platform, only this time the iPhone 5 split into two – a new flagship 5s and a more playful iPhone 5c in a range of bold colours.

In this in-depth iPhone 5s review we assess Apple's most popular smartphone model, offering detailed information and addressing the key areas and important questions that need answering as part of the purchase decision.

You can read this iPhone 5s review from start to finish, but if you want to jump ahead click the links to look in detail at the following areas: the iPhone 5s camera, iPhone security and Touch ID, iPhone 5s processor, the A7 and M7 chips, How much iPhone 5s storage is necessary?, iPhone 5s battery life, Is the iPhone 5s screen big enough? and iPhone 5s price: is the iPhone 5s too expensive?

Watch our iPhone 5s video review below for more information about the iPhone 5s

iPhone 5s review: Camera

Both cameras on the iPhone 5s offer improvements on those on the iPhone 5, and when compared to the iPhone 5c.

The changes that make the biggest impact are to the camera on the back, which gains bigger pixels, a bigger sensor, a new True Tone Flash, and various other hardware and software features.

iPhone 5s iSight camera

iPhone 5s review: camera megapixels

The megapixels of the iPhone camera remain at eight but this is sufficient - don't let anyone tell you that competing smartphones with more megapixels take better pictures on the basis of how many megapixels they offer, because a load of pixels crammed onto a sensor will not create a better image. You can read more about the smartphone megapixel myth here but the crux is that more than 8MP is unnecessary (unless you are planning to blow up the image to a billboard - and actually an award winning iPhone photographer has told us he has no problems using his images on billboards.) The more megapixels you have the bigger the file, and the more space it will take up on your phone.

What Apple has done instead is enlarge those pixels and enlarge the sensor they are on. Larger pixels yield greater electrical output, leading to clearer images in low-light conditions without resorting to messy noise-reduction techniques.

When Apple announced the iPhone 5s it was the first time a smartphone manufacturer had opted to increase pixel size, rather than increase pixels. Since the iPhone 5s launch HTC has bought out the HTC One M8 offering only 4MP, but these pixels are even bigger than Apple's. It seems the idea is catching on.

The larger sensor and a bigger lens serve to let in more light, as does the faster aperture of f/2.2 instead of f/2.4. This faster aperture of f/2.2 really helps with indoor and dusky shooting. When the iPhone 5s launched it was the only smartphone to offer a f/2.2 aperture, since the launch HTC has introduced the HTC One M8 with an even bigger f/2.0 aperture.

iPhone 5s review camera features

Apple has also updated the Camera app in iOS 7 to take advantage of the new iPhone 5s camera hardware and the A7 chip's imaging capabilities. The A7 processor allows the iPhone 5s to focus and capture photos faster than any previous iPhone.

Before you take a picture, the iPhone 5s will perform auto white balance and auto exposure, and will create a dynamic local tone map around the image to get better highlights and shadows. The camera actually takes multiple images and analyses them in real time to see which is the sharpest.

The iPhone 5s also benefits from a clever two-part LED flash. Called True Tone flash, it mixes two light bright LED sources of different temperature to more naturally light your subject, and hopefully avoid the washed-out glare of most simple flash units. One of these lights is a bluish-white, while the other is more yellow. The iPhone's software analyzes the colour temperature of the shot you are about to take – is the room's light warm, cold, or somewhere in between? – and adjusts the intensity of the two LED flashes to match the ambient light as closely as possible.

Apple didn't stop there. The iPhone 5s also has auto image stabilization, which aims to give users a much sharper image.

There's also a new Burst mode, which will take photographs at 10 frames per second until you let go of the shutter. You enable this mode when you hold your finger down on the shutter, images are taken at full-quality and the iPhone picks the best image, although if you disagree you can look through the stack of photos and pick your favourites. Just tap Favorites at the bottom of the screen and select the shots you like. Burst Mode shooting is a nice idea – perfect for photographing children and animals, or to get the perfect group shot, but you could quickly fill up your iPhone with duplicate shots – which isn't ideal if you have the 16GB model. Luckily Apple has made it easy to delete the excess shots – once you have selected your favourite shot, or shots, from those taken you can choose to Keep Everything or Keep Only 1 Favorite.

Series of photos taken with iPhone 5s burst mode

You'll find a similar burst mode on older iPhones – allowing you to leave your finger on the trigger and keep shooting (although not at 10 fps), but those phones will not choose the best image for you, nor is there an easy way to delete the excess images.

Apple's been offering an HDR (high dynamic range) option on the iPhone camera app since iOS 4.1. A high dynamic range image combines a series of photographs, each shot at a different exposure: underexposed where everything is darker, overexposed where it's lighter, and properly exposed in the middle. The best parts of these images are put together into one shot that brings out details in both the shadows and the highlights. The iOS 7.1 update bought a new HDR option to the iPhone 5s. You can now choose from HDR On, HDR Off, or the new option: HDR Auto. When HDR Auto is selected the iPhone will determine whether the image you are taking would benefit from HDR, turning the feature on automatically if it would. 

iPhone 5s review: photo quality

In our photo tests we found picture noise to be dramatically reduced in night-time shots. It almost negates the dual-flash upgrade; as to date we've achieved better results by switching off the flash entirely and relying on natural light, giving great natural, evening shots.

We find that we tend away from using the flash normally when taking low-light photographs for a more natural look, however we found that the new Two Tone Flash on the iPhone 5s remarkably good in these types of settings. Our friends no longer look pale and washed out – it's a revelation.

We pitted the camera of the iPhone 5s against the iPhone 5 and the iPhone 5c to see how the cameras compared. We ran photo comparisons between photos taken with the iPhone 5, iPhone 5c and iPhone 5s in various scenarios. For example, to assess the effect of the various hardware improvements in the iPhone 5s, along with the jump from f/2.4 of/2.2 aperture, we took some low-light photographs. We also took a closer look at the difference between images taken by the three cameras when zoomed into the maximum to see how much of a difference the bigger pixels of the iPhone 5s made and to inspect the detail and colour reproduction. We then examined the photos 'blind' without knowing which phone produced the image we were looking at.

Comparing zoomed in iPhone photos

You can read more about our iPhone photo shootout here, but the conclusion was that, as you would probably expect, the iPhone 5s produced images that were a lot clearer; skin tones were more naturally reproduced; low-light images taken without flash were significantly better; colour reproduction was more accurate; and there was less noise.

We have an HTC One M8 and a Samsung Galaxy S5 in the office and will be running similar photo comparison with the iPhone 5s, so stay tuned for more photo quality assessment.

View the iPhone 5s, 5c, and iPhone 5 photos here on our Macworld Facebook page.

iPhone 5s review: video recording

On the video side, faster processing allows the iPhone 5s camera to capture more frames every second when filming. Switch to Slo Mo in the camera app and the iPhone 5s shoots 720p HD video at 120 frames per second - then replays at a more familiar 30 fps. This gives you the option of slowing all or parts of the video down to a quarter of the speed for an entertaining slow motion effect. It really is as fluid as regular footage. People are going to have a lot of fun with this feature, although we must sacrifice a little resolution. Where normal video is shot in full-HD, Slo Mo captures 1280 x 720-pixel video.

Shooting and creating your slow-motion video is simple. Start by selecting the Slo-Mo mode in the Camera app (swipe across through the options for Pano, Photo, Video to Slow-Mo) and start to shoot video as you would normally. When you've shot the video, the Camera app gives you a set of sliders that let you select the portion of the video you want to play in slow motion. Once you've selected that portion, you have a shareable video that can start in regular speed, shift suddenly to fluid quarter-speed, and then flip back to regular.

The iPhone 5s wasn't the first phone to offer a slow-motion mode, but we've never seen anyone with those Android phones that provide it using the feature (we're guessing because it's not as simple or effective to use). Read about how to use the iPhone 5s Slow-Mo feature here.

iPhone 5s review: iPhone Selfie camera

It's not only the camera on the back of the iPhone 5s that has had an update. The front FaceTime webcam and selfie camera maintains its 1.2-megapixel resolution but gains better low-light sensitivity through larger sensor pixels. We tested the affect of this improvement by making a FaceTime call from a cupboard, and compared to the same set up on an iPhone 5. We were visible when using the iPhone 5s but just a black screen when we did the same with the iPhone 5.

Using iPhone FaceTime

Click through to page 2 of our iPhone 5s review to find out about Touch ID Fingerprint scanner...

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