Geoffrey Wiseman

Touch ID: YMMV

Well, despite the fact that Touch ID has been working very well for me, I can see that your mileage may vary:

My mileage does vary. Perhaps these people simply have Touch ID compatibility problems with their fingers (or what they apply to their fingers). Perhaps they were less able to train the iPhone 5S to recognize their fingers. Perhaps something else is different for them.

Touch ID Fails

Touch ID does fail to recognize your finger. Sometimes multiple times in a row. Sometimes it doesn't seem to notice you've touched the sensor. Sometimes you place it badly. Sometimes you have something on your finger (water, sweat, lotion, food, etc). Sometimes the conditions seem right, but Touch ID just doesn't get it right.

Obviously the frequency with which this happens can have a significant impact on your experience. For me, it's probably at least 1 failure in 15 attempts and it wouldn't surprise me to discover that it's less than 1 in 10, but it's definitely not 1 in 4.

I also find that very rarely does Touch ID fail twice in a row for me, probably less than 1 in 25 attempts, and I don't think I've ever had it fail three or four times in a row for me. I might have had Touch ID not notice my finger, then not recognize my finger, then let me in (three attempts), usually at least partially because of how I placed my finger.

When Touch ID fails, it's almost always just a slight delay while I re-apply my finger or thumb and wait for Touch ID.

Touch ID Speed Varies

Sometimes it seems to take Touch ID a little longer than others. Most of the time, I just wake my phone with the home button and let my thumb rest on the button very slightly longer than I would to unlock it. Most of the time, it unlocks faster than I could have called up Siri had I left the button depressed.

Still, there are times when it seems to take longer. Perhaps I was touching the sensor too lightly, or lifted it imperceptibly, or perhaps Touch ID sensing speed varies somewhat. When it's slow, you might accidentally remove your finger or thumb too soon, forcing you to start all over again.

Touch ID Training Varies

I've registered my fingers and thumbs a few times, in part because I find the training process interesting, but also because I found some of my fingers and thumbs were working better than others, and decided to retrain some of the ones that were working less well. I usually found this improved my results.

It does seem like you can register a digit poorly, reducing your recognition frequency. It seems like some of the people I mentioned up front recognized that and have tried multiple training sessions, so this may not be their problem.

Still, it can be a problem, so if you're having bad luck with a particular digit, perhaps you should try retraining it.

When Touch ID Fails, It's Irritating

Because people are using Touch ID where they wouldn't have used a password, because it's meant to be low-friction and thus be used frequently, and because it's a highlighted feature of the new iPhone 5S, people have high expectations.

When Touch ID fails, when it's slow and requires multiple attempts, it can result in a sharp increased in perceived friction or reduction of convenience. Combine that with the high expectations, and you can practically guarantee that someone spending an extra thirty seconds getting into his or her new iPhone 5S because Touch ID is having a bad day is going to be irritated.

Still the Best Option

Still, despite the above, Touch ID is still the best option for me. It's still lower-friction than passcodes for me, works reasonably reliably and reasonably quickly. Most of the time, it's almost as fast as no passcode and only slightly less convenient.

It's definitely not perfect, and I'd love to see Apple improve on all of these areas for the iPhone 6 and subsequent devices. Still, for my own use, Touch ID makes the iPhone significantly more secure for a marginal loss of convenience. I hope that's how most people experience it.