Along with the OLED display, the biggest new feature on the iPhone X is Face ID and the TrueDepth camera. Everything on the iPhone X revolves around Face ID: it's how you unlock your phone, it's how you use Apple Pay, it's what enables the Animoji (animated emojis), it's the whole reason the notch in the display exists. Apple is so confident in Face ID, it removed its proven and fantastic Touch ID fingerprint scanner entirely, rather than opt for the safer option of moving it to the rear of the phone à la Samsung. That's a bold move, and you know what they say about putting all of your eggs in one basket.
So does Face ID work? Yes... for the most part.
The technology behind Face ID uses an IR light, a dot projector, and a IR camera, collectively called the "TrueDepth camera" all tucked into the notch at the top of screen. When you turn the display on - either by pressing the side button, raising it to wake or double tapping the display - the IR light turns on (you won't see anything because its infrared obviously), and if the IR camera detects a face, the dot projector flashes a pattern of 30,000 dots. The camera then takes a 2D photo, which gets turned into mathematical depth model, sent to the secure authentication chip, and matched against the stored value. This all happens in under a second, and in theory, it's just as fast as Touch ID. Because it uses an IR camera, you don't even need ambient light to activate Face ID - you can do everything in pitch black darkness if you like. You can even wear sunglasses, as long your sunnies allow for infrared light to pass through them.
Setting up Face ID is actually faster and simpler than setting up Touch ID. The phone displays a circular border around your face, and you simply move around until a series of lines around that circle turn green. Do that twice, and you’re done.
For the most part Face ID works great. Raise the phone, look at it, and your screen unlocks - indicated by a little padlock unlocking animation. A minor annoyance is that unlocking the display doesn't send you straight to the home screen like Touch ID - instead you have to swipe up from the white line at the bottom of the display.
Having said that, it's not perfect and over the past week I've run into a bunch of scenarios where I was longing for Touch ID. I normally have my phone sitting on my table at work, but with the iPhone X I need to pick it up or move my face over it to unlock it. With Touch ID, I would just leave it on the table and unlock it with my finger. I've gotten used to pulling my iPhone out of my pocket with my thumb already on Touch ID too, so it's unlocked by the time I'm looking at it. However with the X I need to pull it out, then look at it, then swipe up to get to the home screen, which takes a little longer than usual.
I've got a bad habit of checking my phone throughout the night, but I generally sleep on my side, and unlike Touch ID, Face ID doesn't work in landscape mode (or upside down). Additionally, according to Apple, Face ID works best at a distance of 25 to 50 centimeters, so if I'm in bed and I want to unlock the X I have to roll onto my back, then hold the phone up in the air above my face to get it to unlock. Unsurprisingly, after the first few nights of this, I've started just letting Face ID fail and then inputting my pincode.
Speaking of unlocking the X at night, contrary to what you might think, (other than when I'm lying in bed) I've actually found Face ID to be more accurate in the dark. This actually makes sense because that IR projector can easily light up your face in the dark, but if you're standing under bright florescent lights or even under direct sunlight (which contains its own infrared light beams), this light can interfere with the X's IR camera. The few times Face ID has failed to unlock for me has been under bright sunlight and when I was standing next to a neon signboard display.
All things considered, Face ID is good enough to replace Touch ID (and according to Apple it's actually a lot more secure too - unless you have an identical twin), but it's not perfect yet. It also takes a bit of getting used to, and you'll definitely have to change certain habits.
I've shown Apple's Animoji feature to over a dozen people in the past week and when asked what they thought of it, the response has been polarizing: either "I love it!" or "That's really dumb". Personally speaking, I can appreciate the technology powering Animoji (it's basically like having a tiny Xbox Kinect in your phone, which is amazing when you look at how big the original Kinect is) but the novelty didn't hold my attention for very long.
The most impressive thing about Animoji is just how well the TrueDepth camera tracks your eyes and facial expressions. It's perfectly in sync with the animation and captures even small nuances really well. If you do like Animojis, it's worth pointing out that while Animojis are only available natively in iMessage, you can actually send them over other messaging platforms by saving them as MOV files and sending them as videos.
The X runs on iOS 11 just like the 8 and 8 Plus, but there have been a few tweaks - mainly to navigation - to accommodate the lack of a home button.
At the bottom of every app you'll see a white line. Swipe up from this line to go back to the home page, or swipe left or right along the line to switch between apps. To open the Control Center, you'll need to swipe down from the top right of the display. To open the Notifications pane you swipe down from the top left. To launch the app switcher you swipe up from the bottom of the screen and then do a 3D Touch hard press.
To activate Reachability mode, which pulls the top of the screen down to make one-handed usage easier, you have to swipe down on the bottom edge of the display. I found this a little inconsistent as it seems like the area you can swipe down from is quite small.
Other than these changes, the X's UI is basically exactly the same as what you get from the 8 and 8 Plus.
For a more in-depth look at iOS 11 check out our iPhone 8 review and these articles: