Review: iPhone Fingerprint Sensor Worth Extra Cost

Passcodes are such a pain that I've relaxed the security settings on my Android phone. I'm willing to forgo the extra safety, just so I'm asked to punch in the code less often. When I got my hands on Apple's new iPhone 5S, one of the first things I tried was a feature that allows you to bypass the passcode using a fingerprint.

I had a lot of fun unlocking the phone over and over again. Who knew biometric authentication could be such a blast?

The fingerprint sensor alone is worth the extra $100 you'll pay for the 5S over an iPhone 5C. Both phones will come out Friday. In the week I've had with both, I've also been impressed with the better camera and slow-motion video in the 5S.

The 5C, meanwhile, is largely last year's iPhone 5 with a plastic casing instead of aluminum and glass. This isn't cheap plastic, but a type offering the slippery feel of a shiny ceramic tile. It comes in five colors.

Both phones come with iOS 7, the most radical change to Apple's operating system software for mobile devices since its 2007 debut. Many of the changes are cosmetic, but there are functional improvements such as easier access to frequently used settings and apps.

 

Forget the new iPhone, iOS 7 Will Change Your Current iPhone

I will review iOS 7 separately. Many existing iPhone users won't need more than the free update, which is available starting Wednesday. Neither the 5C nor the 5S offers improvements on the screen size, which remains at 4 inches diagonally. But new features and new colors may draw you to one of these new iPhones.

— IPHONE 5S (available in silver, gold or gray; starts at $199 with two-year service contract, or $649 without a contract):

When you set up the 5S, you're asked to tap the home button with a finger several times so the phone can create a mathematical representation of your print. To unlock the phone, you simply tap the home button, and the phone will compare the two taps. You can tap from any angle, even sideways or upside down. This fingerprint ID also works as a way to authenticate the purchase of apps and content within apps.

What You Need to Know About Using iOS 7

For security reasons, there are still times you'll need your four-digit passcode, including after 48 hours of inactivity and before adding a new fingerprint. If the phone fails to recognize your print, you can always use the passcode. I had trouble only when my fingers were wet or greasy. One evening, I ordered pizza with an oily pepperoni topping and ate it without a napkin. The fingerprint sensor worked after one slice, but not two. Indian naan bread also threw off the sensor.

Apple says it stores the print data on your phone, in a place that's inaccessible to other apps or to Apple's remote servers. The company also says it's not possible to convert a fingerprint from a police file into something the phone will recognize, as the sensor reads a sub-epidermal layer of the finger. And the finger needs to be live — cutting off a thumb won't work.

I'm convinced Apple has given a lot of thought to security. If you're still uneasy about the fingerprint scan, you can stick with the passcode. The feature is optional.