The Galaxy S8 has face recognition and iris scanning, and you have to choose one

Galaxy S8 facial recognition
Galaxy S8 facial recognition (Image credit: Android Central)

The Galaxy S8 contains more ways than ever to keep your content safely locked behind a password: in addition to the traditional PIN, pattern or password option (cumulatively the most secure), there's fingerprint recognition, iris scanning (which debuted on the Galaxy Note 7) and, oldie-but-goodie, face recognition.

In the beginning...

Back in 2011, Google debuted support for face recognition as an unlock option on select devices. It was available on phones like the Galaxy Nexus, HTC EVO 4G LTE and HTC One X, but eventually manufacturers stopped supporting it because it didn't work very well.

The idea of face recognition is a good one: all phones have a front-facing camera, and all (most) people have unique faces, and phones are computers that can figure out that the person stored in the phone is the same one holding his or her phone in front of the camera. But two things stopped it from gaining popularity: for a long time, front-facing cameras had small, low-quality sensors, making them slow and generally terrible in poor lighting. You need your unlock method to work all the time, not just in particular lighting. The second reason is less obvious: the proliferation of fingerprint sensors made alternative forms of fast-but-relatively-safe unlock methods less necessary.

Then came Smart Lock

When Lollipop debuted in 2015, Google created something called Smart Lock, a service across its major platforms (Android, Chromebooks, and Chrome OS) to make it easier for people to unlock their devices without passwords. On Android, that early and little-used face recognition feature that debuted in 2011 eventually became just another part of Google Play Services alongside on-body detection, trusted voice, trusted places, and trusted devices. But still, even today, very few people use it.

Fingerprint sensors made face unlock less necessary — and way less popular. Until now.

To be fair, Google's implementation hasn't always been very good — in fact, it's still pretty unreliable on most phones — but most people don't even know it's there, buried as it is within Google's Play Services. It's also not included on every device, which makes advertising the feature a hit-and-miss affair. Trusted places — your house, or workplace — uses location, which is more easily detectable, and trusted devices allows a smartwatch or other Bluetooth device to act as a nearby authenticator. Again, super simple. With fingerprint sensors being integrated on most devices, facial recognition just isn't that necessary.

What's old is new(s) again

When the Galaxy Note 7 was released last year, it arrived with a fair amount of buzz surrounding its iris scanner. But because the scanner actually matched the details from the inside of your eye against a stored copy — which is nearly impossible to duplicate or imitate — it worked slowly, and often failed. So Samsung decided to bring back the face scanner in the Galaxy S8, and improve upon Google's implementation in a number of ways.

The Galaxy Note 7's iris scanner failed a lot. But it was still a great idea worth pursuing.

Face scanning works by taking a photo of your whole face, and using the front-facing camera to match specific details to the live photo in front of it. On the Galaxy S8, this works incredibly quickly — far quicker than any other face unlock method, and often more quickly than the fingerprint sensor — for a couple of reasons. First, the Galaxy S8 is just plain fast — its Snapdragon 835 or Exynos 8895 chips have incredibly advanced image signal processors that perform the work in a fraction of the time it took just a few years ago. And the 8MP front-facing camera inside the Galaxy S8, which has autofocus and is therefore much more likely to find a subject lock.

But as you may have seen plastered around the internet, face recognition is not foolproof. Indeed, it's fairly easy to spoof if you have a high-resolution photo of the subject, and some persistence. This isn't to say that opening Facebook and showing a photo of your friend to his phone while he's in the bathroom will unlock it (let's be honest, too, he's bringing that phone with him to the bathroom) but Samsung doesn't recommend you use face unlock if you have sensitive material on the phone.

That said, it's so fast, and much more likely to find a match in low-light situations, a common scenario that Note 7 owners found themselves frustrated by with the iris scanner last year.

Focusing on the iris

Iris scanning is a more secure form of biometric authentication, and is likely more secure than a fingerprint since it is basically impossible to recreate, even using the most advanced methods.

The iris scanner has made a return to the Galaxy S8 after it ignominiously disappeared in the Note 7 last fall. It's also much, much faster than before — which is good, because the damn thing needed it.

Iris scanning on the Galaxy S8 is at least twice as fast as the Note 7, and fails less in low light. In other words, you'll want to use it.

On the Galaxy S8, I've found iris scanning to be very reliable and quite fast most of the time, though not as instantaneous as a fingerprint sensor or face unlock. That said, I've been impressed with its ability to unlock in low light — the iris scanner likely uses a combination of the dedicated infrared sensor and front-facing camera to get a match — which had led to considerably fewer moments of frustration.

I've also noticed that the iris scanner, while it still needs to have your eyes in its sights, doesn't need to be perfectly aligned the way the Note 7's did; I can have my hands close to my chest and tilt the phone up towards me, and as long as my eyes are in the viewfinder it unlocks most of the time. It's still not perfect, and I occasionally find myself having to find the fingerprint sensor to finish the job, but it's rare.

You can only choose one

For safety reasons, you can only choose one method of facial unlocking on the Galaxy S8: face recognition or iris scanning.

  • If you're concerned with security above all else, use the iris scanner.
  • if you're concerned with speed above all else, use the face recognition.

Of course, either of these methods can be combined with the existing fingerprint unlock, which despite being on the back is fairly easy to reach and may end up being faster than either. The main upside to the visage-based methods is that you don't have to poke around on the back of the phone for the fingerprint sensor; you can merely turn on your phone, look at the camera, and go.

Daniel Bader was a former Android Central Editor-in-Chief and Executive Editor for iMore and Windows Central. 

62 Comments
  • I personally love the smart unlock. Works great with my Gear S3.
  • I never had issues with the iris scanner on the N7. It was really fast and worked great in and outside. Even my wife never complained about it and she used it more than the finger print sensor. Looking forward to using it again soon.
  • But nothing is more reliable as fps
    Samsung could have just placed the fps below the camera to make things easy
  • Yeah exactly. Not sure why they didn't go with a small squircle underneath the camera. It wouldn't have looked bad and they could have centered it.
  • I could have been due to the NFC and MST chips for Samsung Pay.
  • naw it cant be that cuz the Nexus 6P has the fingerprint scanner in the same place and the NFC chip is right above it and i can honestly say ive never had an NFC chip work better on any phone . coming from several blackberrys and LG G3
  • And there is a whole other module that needs to be there (MST) that the nexus doesn't have. The MST module seems like the most likely reason for the high fps.
  • Not easy to change the whole motherboard setup last minute. I am sure they would have put it in a better position if it was physically possible. Only because the onscreen fps didn't work out in time, they had to move the fps at the back. I am sure for Note8, the fps will be on-display itself or at a better position on back.
  • Smart unlock is only reliable on Bluetooth. I wish they would include WiFi too.
  • I thought it's also available through WiFi. I have had to reject prompts to disable automatic unlock when on my home WiFi.
  • What phone do you have? I believe my old Moto did that, but nothing since.
  • Smart unlock is no longer supported on nougat. I'm referring to Google's "Smart Lock"Nexus 6P 7.1.2 beta. The only options are and have been under device are, Bluetooth, and NFC.
  • Try Tasker. Once you learn how to use it you can automate things for any situation. One app to rule them all. I can't live without it.
  • I have Tasker. I'll give it try. Thanks!
  • http://forums.androidcentral.com/ambassador-guides-tips-how-s/562081-how... If you are running Nougat you may have issues with Secure Settings and may want to try SecureTask.
  • not some great "test"!
    why is nothing said about using it with glasses!?
  • I use both with glasses and they are fine. No problems at all.
  • I haven't used the iris scanner in practical situations, but trying it at my local retailer with my Oakley Carbon Blades, it saw my eyes right through the lenses. I can only imagine, if it worked that well with reflective lenses, then it should work rather well with regular lenses. I do have a feeling, from what I saw testing the iris scanner, that it uses IR as a light source.
  • Note 7 iris scanner worked through my dark Oakley sunglasses
  • That's great to know - I'm really looking forward to testing this out. Does it also work with the phone in both portrait and landscape, or does it have to be in portrait?
  • Neither. I don't trust any security method that can be ruined by a moustache, and iris recognition is just too new and unreliable.
  • Actually, it's not new. It's new on a PHONE but the tech isn't new at all. It's been around for years. Do your homework before you say stuff like that.
  • Really? On an article about the S8 you really need me to qualify that I'm talking about phones and not airports? Leave the talk to the guy in red, you've clearly taken one too many question mark blocks to the head.
  • I didn't know that iris scanner could be affected by a mustache. How long have been using it on your s8?
  • Been using the galaxy S8 for the past 15 or so years... The iris scanner has never worked when I've had a moustache. I believe it's because the imp that uses a small telescope to verify your eye gets too distracted by how glorious and voluminous it is, if your 'stache is thin and lame it'll probably work fine.
  • Figures, someone who talks without any research or actual usage. Now I know what comments to ignore. Thanks
  • Ah, so you weren't joking.... My mistake, I gave you the benefit of the doubt. The first part of my comment was about facial recognition... It was a somewhat flippant way of pointing out how easy it is to screw up. The second part (maybe you genuinely missed the comma?) Was about the iris scanner. I don't have personal experience, but I have done research, and if you do the same you'll see that it is pretty unreliable if you try to use it in different lighting conditions. Or if you wear sunglasses... Summer here kids. Feel free to ignore my comments, it seems they go over your head anyway.
  • This is purely anecdotal, but I have been using an iris scanner on my phone for over a year now and it's been reliable in even low light conditions. In fact it works more often, albeit slower, than a fingerprint sensor. Fingerprint sensor doesn't work if you have dirt or water on your fingers.
  • Well, the only time I've known someone to use it was on a note 7 and they seemed to have trouble in direct sunlight... Personally my hands have never been grubby enough to disrupt a fingerprint scanner, but it is a fair point that no method is perfect. But the fingerprint sensor is what I'll stick to for now, I don't see any point in using an iris scanner over it.
  • I don't know how the facial recognition on the S8 works, but I'd be surprised if it gets confused by a moustache. In general, facial recognition is much more sophisticated, and looks at spacial relationships between multiple points, including multiple points on the nose (e.g., the tip of the nose, the bridge, the width of the front and total width, length, eyes (distance between them, width and height of each eye),, eyebrows (width, height, thickness, lips, and chin, sometimes ears and hairline. And the distances and angles between all of those items. So the distance between the eyes, between the inside of each eye and the inside and outside of each eyebrow and multiple points on the nose, lips, etc. There are literally thousands of points of comparison in the best systems. If you're trying to identify a face in a database of hundreds of thousands or millions of people, it gets more complicated, but if you're trying a 1 to 1 match it works quite well. I've seen demonstrations (I worked for a client that uses it extensively, matching individuals against a large database), and it worked even when people changed hairstyles to cover the forehead and eyebrows, grew or shaved off beards, tried changing the shape of the mouth by pursing their lips, etc.
  • I've been using iris recognition on my Lumia 950 for over a year now. Its not new.
  • Over a year? That's new. Maybe we judge it differently...
  • So I don't HAVE to choose one, I can ONLY choose one. The title of the article makes it sound like S8 users are forced to choose one or the other, which is not the case. That actually the only reason I clicked in the article, because I thought it was a crazy idea to be forced to choose one or the other.
  • You can still use all the other forms of security unlock with the iris scanner no different then with my note 7 Posted via note 5 are gs7 edge the beast
  • You are forced to choose one or the other if you choose to use one of those unlock methods.
  • No biometric means of unlock is protected by the 5th Amendment.
  • Perhaps I'm paranoid but this is one reason I'd avoid using both iris and fingerprint recognition on the phone (face is a non-starter) -- at least while traveling. I'm a US resident but not citizen, which puts me in a slightly higher risk bracket for potentially being pulled aside at immigration. And recent... "events"... have made me more aware of this. To be fair, I do use Windows Hello on my laptop because I'm confident of the day-to-day level of security, and it's a lot quicker than entering my full password. But I'm considering disabling it, too, for international travel.
  • There is one simple way to avoid this issue is most but not all circumstances. When you reboot the phone it usually, atleast on my last 2 phones with fingerprint sensors, requires your password or pin. I personally use a long password. So in a situation where you are concerned, just turn your phone off. Next time it's turned on it will require your password which is protected.
  • If you're entering the U.S. at a port of entry (e.g., airport), it doesn't matter how you lock your phone or computer. CBP inspectors have the right to force you to unlock your electronics, or be held until you do. I don't agree with the policy, but it's been upheld in the federal courts. Even U.S. citizens have been forced to unlock and turn over their devices.
  • Pretty sure it's not as cut and dried as that. The courts have ruled both for and against CBP powers at different times, so the matter still isn't settled. And I'm fairly sure (but too sleepy to find it right now) that there are limits on how long they can personally detain you (though not your phone/laptop, which they will happily confiscate). What it comes down to is that they *do* have the ability to basically strong-arm you into giving up your password: by detaining you for hours; with the threat of long-term confiscation of the device (we're talking months); with the threat of being subjected to additional scrutiny at future border crossings; with the threat of refusing you entry (if you're a foreign visitor, which could also cause problems for future entry attempts); with the threat of legal implications to your residency status should you be charged with a misdemeanor for refusing to assist them (if you're US resident); and simply by implying that they have the legal right to demand your password despite the law still being unclear. tl;dr -- Nobody's going to prison for refusing to give up a password, but CBP can certainly threaten to make your life varying levels of hell if you don't and if they feel like it, depending on your personal circumstances.
  • Other than it being cool, I can't see why you'd use the face/Iris scanner regularly over the fp sensor, which is faster and more reliable. Yeah, the placement is weird (why, Samsung??), but you'll get used to it. The only exception I could see is women with very small hands, who may have legitimate trouble reaching it on a phone as tall as the S8.
  • I felt the same way when they repositioned the flash/sensor to the side of the camera lens. It just looks out of place. It looked better when positioned underneath the camera as on my Note 4.
  • But having the light source under the lens is absolutely the worst place in terms of lighting a human face. Is how the phone looks more important than how the photo looks?
  • What about men with small hand, they don't count?
    Joking aside, I find the fp sensor to be just as unreliable for different reasons.
  • With Smart Lock, you shouldn't have to unlock your phone all that much, right? I'm going to use that and Iris, since I'm mainly concerned about my phone being secured when it's away from me.
  • Can't wait for my S8Plus
  • Let us know if you were able to finish your sandwich before having to recharge
  • I use Smart Unlock, and will likely use facial recognition if I pick an S8. The reality is that there is not enough interesting on my phone, nor enough people with access to it who want to see what is on it to worry me.
  • I'd feel honored if someone went through all that trouble to break into my phone! I'd still probably just remote wipe it if I lost my phone for longer than an hour or so.. I love they give us the choices though, even if one of the options isn't that secure, it would still keep the kids from getting on it when I wasn't looking.. I think it would be great if they would combine Iris with facial recognition, that would give it even more security!
  • As well as the iris scanner worked on my Note 7, it was still much more convenient to unlock with the FPS. It worked as simple as placing your thumb in a natural position as you picked up the phone or with your index finger if the phone was to remain laying flat. With the new position of the FPS other security measures are being pushed because it's known to no longer be as convenient. Step backwards. Simple as that.
  • Ugh. The Smart Lock replies are kind of annoying. Some of us want to keep our devices locked at all times for various reasons. I didn't like the iris scanner on the Note 7. It felt like it was going to fry my eyeballs.
  • Another vote for smart lock at work and at home. Kind of sad you can't trust the people in your home and work place Posted via note 5 are gs7 edge the beast
  • It's not so much about trust, but privacy
  • The iris scanner to me got so fast that I didn't use the finger scanner much at all . Now that it's twice as fast... that's a no brainer for me I don't need know stinking finger scanner. Oh and by the way I played with the s8 and it's so narrow that the finger scanner was really easy to reach Posted via note 5 are gs7 edge the beast
  • Does the face recognition work in the dark, like the iris scanner does???
    If it does I'm using the face unlock
    Seems faster
    Plus shining an infrared light into my irises 50-100 times a day for a whole
    Sounds like e health risk to me
    (any studies on this?)
    I only used the iris scanner on my note 7 when I was wearing gloves
  • Do you ever go outdoors? If so, you're shining infrared light into your eyes all the time.
  • LOL
  • I purchase the S8 plus on 5/4/ 17, After the 1st day-of use after setting up the Iris scanner I noticed discomfort in one of my eyes that felt like an eyelash was stuck underneath your eyelid. After I checked it more I noticed brown spot where the "pain" was And another Brown spot on the other eye. These to spot lined up exactly where the Iris scanner "reads" my eyes at the position and distance that I hold my phone. After the 2nd day I had what could-be described as real pain. Turned off and shut down. I was curious to see if anyone else had experienced anything like this and also to warn everyone do not use the Iris scanner
  • I hardly ever use the fingerprint scanner, but I loved the iris scanner from having the n7 for that short time. That's one of the features I missed.
  • I'm gonna use the face detector it looks super fast and is pretty secure for most people's needs, I don't plain to put government clearance type stuff on my phone . Don't know about you guys but I'm good with just that. Posted via note 5 are gs7 edge the beast
  • I remember when face unlock was a thing on Android OS back in 2012
  • If the police or some other "authority" wants to unlock your phone and you are using the fingerprint, face, or iris scanner to unlock the phone, then all they need to do is make you touch the sensor, or look at your phone and it is unlocked. The best method is a long pin or password. The authorities cannot compel you to provide the information so your data should remain relatively safe.