Galaxy S8 Fingerprint vs Face Recognition vs Iris Scanner: What's Best?

When it comes to unlocking your Galaxy S8 with biometric security, there's no shortage of options. But which one is the most convenient, secure and reliable?

With the S8, there are three ways to log in to your device other than the usual swipe, password, pin code and pattern options. There's the fingerprint scanner on the back, face recognition (which uses the phone's front camera) and a dedicated iris scanner up front. Note that you can't have face recognition and iris scanning both active at the same time; you have to choose one. Here are the pros and cons of each method.

Fingerprint Sensor

Pros: If you place your finger on the sensor, you can unlock the phone instantaneously — without even having to press the power button. You can also register multiple fingerprints and use your fingerprint to verify your Samsung account, instead of entering a password. Plus, you can use your fingerprint to pay for items via Samsung Pay.

Cons: Samsung's decision to place the fingerprint sensor right next to the rear camera can make it difficult to find the sesnor by feel. In addition, as with other fingerprint sensors we've tested, this one has trouble recognizing your digits if your hands are sweaty or greasy.

MORE: Samsung Galaxy S8 Features to Enable and Disable

Face Recognition

Pros: Face recognition on the Galaxy S8 is pretty easy to set up and it works well under low to moderate lighting.

Cons: This is the least secure option of the bunch, as the face recognition can be fooled with a picture. Plus, the feature had trouble recognizing my mug both in bright sunlight and in the dark. And, unlike iris scanning, face recognition doesn't support Samsung Pay.

Iris Scanner

Pros: First introduced on the Galaxy Note 7, the iris scanner option scans your eyes to log you into the Galaxy S8. It works much more quickly this time around and was actually faster than Face Recognition in our tests. If you use Samsung Pay, you can use the iris scanner to authenticate purchases. Bonus: the iris scanner works in the dark, unlike face recognition.

Cons: Forget about using the iris scanner in direct sunlight. We couldn't get it to work, as it's very difficult to open your eyes fully when you're squinting.

MORE: Galaxy S8 Review

Overall Recommendation

Based on our testing, the best way to unlock your Galaxy S8 is a combination of using the iris scanner and fingerprint reader. You can have both options turned on simultaneously, both are fast and both support Samsung Pay. The iris scanner doesn't work in direct sunlight, so you can always reach around to the back of the phone to use the fingerprint reader in those situations.

Mark Spoonauer

Mark Spoonauer is the global editor in chief of Tom's Guide and has covered technology for over 20 years. In addition to overseeing the direction of Tom's Guide, Mark specializes in covering all things mobile, having reviewed dozens of smartphones and other gadgets. He has spoken at key industry events and appears regularly on TV to discuss the latest trends, including Cheddar, Fox Business and other outlets. Mark was previously editor in chief of Laptop Mag, and his work has appeared in Wired, Popular Science and Inc. Follow him on Twitter at @mspoonauer.