A brand new feature is immediately exciting, but we're tempering our expectations for daily use.
With all of the Note 7's similarities to the Galaxy S7 edge, one big feature that sets it apart is its much-rumored iris scanner — something that seems extremely sci-fi but in reality isn't all that complicated. In fact, we've seen phones for well over a year now use iris scanners, though they haven't exactly been the highest end or widely purchased models: phones like the Alcatel Idol 3, ZTE Grand S3 and Lumia 950/950XL, for example.
The Note 7's iris scanner uses two distinct pieces of hardware — a specialized camera, which is separate from the front-facing selfie camera, and an infrared light to the left of it. When the phone wants to recognize your irises (and yes, it prefers to see both eyes), the infrared light shines into your eyes and the camera reads the pattern of your irises. Because the light is infrared you don't perceive it when you're looking at it (like "laser" autofocus for cameras), and it also gives the camera a better ability to see your eyes in a variety of situations. The iris scanner is set up to work through glasses, as I saw demonstrated several times. This is one feature that's going to take days or weeks of use to see how it actually performs, but in quick testing it worked as advertised.
The iris scanner feels a bit like a sideshow tech demo and a tacked-on feature
As far as the supporting software goes, the iris scanner isn't as widely supported as fingerprint sensors on modern Android phones. With the iris scanner you can unlock the Galaxy Note 7's lock screen, log into your Samsung account and unlock certain Samsung apps — the key example is the new "secure folder" that's available as part of the KNOX platform, in which you can lock away specific content into a secured, sandboxed area. In terms of usability, you can think of the iris scanner as being in the same situation as Samsung's older fingerprint scanners were before Marshmallow arrived: its functionality is limited entirely to Samsung's own apps.
Thankfully this iris scanner is available alongside, not in place of, the fingerprint sensor that's still embedded in the Note's home button. But because of that, it really does make the iris scanner feel a bit like a sideshow, and I have to wonder how many will choose to use it as the main unlock method. No matter how fast it is, it's never going to be as fast as just pressing your finger on the home button for a fraction of a second, nor will it be as reliable in various conditions — like in cases of very low light, or when you can't look directly at your phone.
I love the initiative Samsung is taking to try new things, but this one doesn't immediately feel like one that's going to stick. After a while of using it every day to unlock the Note 7, perhaps it will grow on me.