First introduced with the iPhone X, Face ID is a complex biometric scanner built into the front camera system of Apple's iPhone.
It may take a week or two to adjust to no longer placing a finger on the home button to unlock your phone, but once you get used to Face ID, you'll forget all about it.
Before we dive into the setup process, let's take a quick (and not all that nerdy) look at how it works.
How it works
Apple's TrueDepth camera system is made up of several components, as you can see in the screenshot above. Working in tandem, the sensors and components project 30,000 infrared dots onto your face, which are then used to map out all of its curves and wrinkles. During initial setup of Face ID, that map is converted to a 2D image that the iPhone then uses as a master key.
Every time you wake the screen on your iPhone, dots are projected, your face is mapped, and it's compared to the master key created during setup. If it matches, your iPhone unlocks. If not, you're asked to try again or enter a passcode to unlock the phone.
And all of that happens in milliseconds.
When it's used
The most common use case for Face ID is unlocking your iPhone, instead of using a PIN. Whether you tap on the display while your phone is sitting on your desk, or you bring the phone up to view notifications, Face ID is activated and attempting to verify it's you looking at the phone.
Notice the Face ID logo at the bottom of the screen? Whenever you see it, Face ID is actively trying to scan your face. Outside of unlocking your iPhone, Face ID is used to:
- Authorize Apple Pay
- Approve purchases in the App Store, iTunes, iBooks
- Sign into third-party apps, such as banking or password managing apps
Another cool feature about Face ID is that when your appearance changes slightly -- say your hair is done differently or you shaved your beard -- Face ID might fail. However, when you enter your passcode after Face ID failed to recognize you, it uses that scan to teach itself that your appearance has changed slightly and next time it should recognize you without issue.
When setting up your iPhone XS (or XS Max, XR or X) for the first time, you'll be asked if you want to use Face ID. If you chose not to, you can still enable Face ID through the Settings app later on. Regardless of when you set up Face ID, the process is the same.
First, you'll be asked to set a passcode that you'll be able to use as a fallback authentication method if Face ID has trouble recognizing you, after your iPhone is restarted, or if your iPhone hasn't been unlocked in 48 hours.
To register your face with Face ID, hold your phone between 10 and 20 inches away from your face. With your face centered in the circle, move your head around until the scan is complete. It's easiest to slowly move in a circle. You'll be asked to complete a second scan, after which Face ID setup will be complete.
A look at the settings
On your iPhone, open the Settings app and select Face ID & Passcode. Enter your passcode when prompted.
Face ID's settings allow you to enable or disable when the feature is used, as well as add an alternate appearance (could be used to give your partner access to your phone, for example).
If you find issues with using Face ID when you have sunglasses on, you can disable Require Attention for Face ID, which makes it possible to unlock your phone even when the True Depth camera cannot see your eyes.
Because Face ID features affect your overall security, take a few minutes to go through each option and ensure that it's set up how you want.