Touch ID: How to Correctly Give Your iPhone 5s the Finger

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For some people, the iPhone 5s fingerprint recognition in Touch ID can be less than perfect, occasionally frustrating. Either it doesn't work the first time, all the time, or defining multiple fingers doesn't help. Here's how I learned to make it work, first time, every time, with just one finger.

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I haven't heard of many complaints about Touch ID on the iPhone 5s. However, if you're like me, you may have had some frustrations getting it to always work the first time. It's just plain annoying to have Touch ID fail to recognize your finger the first time, and if you fail three times, you'll then have to enter your regular pass code — something you could have entered in the first place with less hassle.

This is less than optimum when showing off Touch ID to friends. One doesn't want to get Doonesburried.

In my case, it seemed that I was only getting about a 70 percent success rate with my right index finger. (Less, of course, during my demos. Murphy's Law.) I tried to make sure my finger was clean and dry every time. That didn't help, and I wanted more.

After some initial trials, I followed the consensus advice to define a second finger, say, the thumb. If my index finger failed, I'd try the thumb. Often, after my index finger failed, my thumb would too. (I followed the advice about how to move the finger around during training -- to no avail.)

I decided that the best thing to do was to bide my time and wait to see what developed in the Apple tech community.

A Eureka Moment

Yesterday, I tried defining my right index finger twice. That is, I deleted all previous fingerprints, started from scratch, and then defined my right index finger. I labelled it R.index1. Then I did it all over again and labelled the second one R.index2. Since then, I have been able to authenticate on the 5s with my right index finger the first time, every time with zero failures. None.

Discussion

My theory is that if the first definition fails, the 5s tries the second definition. You may have defined the second one for a different finger, but the 5s doesn't know which finger you'll try first. So perhaps it just tries all of them for each press.

By using the same finger with two definitions, if the first one fails, the second one might succeed by some quirk of the recognition algorithm. It's like rolling dice. If the chance of rolling a 6 is 1/6, then the chances of rolling two 6's in a row is 1/36. By analogy to the 5s, the chance of failure is greatly reduced with two full definitions (two rolls) of one finger.

Again, this is just my theory. What I do know is that for two days now, I have had zero failures when authenticating on my iPhone 5s. If I ever do get a failure, I'll definitely try adding a third definition for the same finger. That should reduce the failure rate even further.

If you've been frustrated with a less that perfect success rate, and this trick works for you, let us know in the comments below.

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Touch ID tech diagram via Apple.

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10 Comments Leave Your Own

Laurie Fleming

Genius! Thank you!

cjpitt

I don’t have the latest iPhone…but the gym recently started using a fingerprint scanner when you enter. It works maybe half the time. A work-in-progress…

Bob LeVitus

Keep us posted, John. I’ve done what you describe a couple of times and it seems to work for a few days/weeks, but then recognition declines. I have stored two fingerprints for each thumb (4 total) with no better results. I think the algorithm tries to improve its recognition over time, but only succeeds in making things worse. YMMV, of course.

Thanks in advance.

bbbo

Doonesburried? Oh come on…
A link…? A definition…? Something…?

John Martellaro
John Martellaro

Bob: I saw that deterioration before when I had one finger defined. However, I haven’t seen it yet with two defined!  If I do, I’ll update.

Dave Hamilton

John, an even better solution is to do single entries for each of your fingers and “overtrain” your iPhone. This was first discovered by Steve Gibson of SecurityNow, and we discussed it on Mac Geek Gab recently, too.

The net is that when you’re on that screen where you can rename your fingers, you can also touch he sensor and it will highlight the finger that matches. Each time you do this, though, the sensor gets more and more trained. Keep touching that thing for an hour when you’re on a conference call and then your iphone will never have trouble recognizing you.

I used to do the multiple entries thing, but it fails after about a week. You’ll see. wink since I did this single, over-trained entry per finger, though, my fingers work all the time, and have for weeks.

Bob LeVitus

Thank you John and Dave. I’ll try overtraining. Thanks for the tip.

paikinho

Nice tip.
I find that I have trouble after a few different times.
Shovelling snow gets my hands wet and my prints seem to change. (swell)
Same for washing dishes or post showers.
Also if my fingers get a bit dirty or oily from something the fingerprint starts to miscue.
I like the idea of making 2 prints of the same finger…. will give it a go .
Probably r thumb1 r thumb2 r index & L thumb.
Anything is worth getting a bit of a bump in accuracy.

Adrian Keller

Thank you. That helped SO much :D

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