Face ID uses a combination of hardware and software to identify you. An infrared dot projector creates an invisible grid of 30,000 dots across your face, while infrared cameras capture the pattern. This depth data is compared against stored facial information encrypted on your device to unlock it or authenticate purchases.
The system works in most lighting conditions, including darkness, because it relies on infrared rather than visible light. It learns how your face changes over time due to hairstyles, makeup or glasses, adjusting its recognition model accordingly.
Why it matters for buyers: Face ID is faster than fingerprint unlocking and harder to defeat with photographs or masks. However, it requires you to look at the screen, whereas Touch ID fingerprint sensors work when your phone is on a table. Some users find it slower during video calls or when wearing face coverings.
Common gotchas: Face ID performs poorly if you wear thick or tinted sunglasses. Identical twins can unlock each other's phones. The system requires a clear view of your face and doesn't work well at extreme angles. Some find it intrusive compared to fingerprint recognition.
What to know when buying: Face ID quality varies by model. Newer iPhones with improved sensors are more reliable than older versions. If you wear glasses regularly or live somewhere very cold, test Face ID in those conditions before purchasing.