Q: I was at a coffee shop the other day and saw the coolest thing that I didn’t think you could do with an iPhone. This guy had his iPhone down on the table, and somebody called and the camera light started flashing. I’m positive it was an iPhone he was using, but I didn’t know that the iPhone could do that, and I can’t find a setting anywhere for it.
Is it an app? I’ve found stuff on the App Store that lets me strobe the camera light, but I can’t find anything that lets me turn it on when a call comes in. How does this work?

A: The ability to make the camera LED flash when an incoming call or other notification comes in actually is a feature built into the iPhone, but it’s not really located in an obvious place, as Apple designed it specifically for those users with hearing problems who may not be able to hear their iPhone ringing, even at the loudest volume. As a result, the setting lives not under Sounds or Notifications, where you might expect it to be, but in the Accessibility section, found under Settings, General.
You’ll find a number of settings in this area designed to make the iPhone easier to use for people with various special needs, and the LED Flash for Alerts feature is among them, near the bottom under the “Hearing” heading. Simply toggle it on and your iPhone will flash the camera LED every time it would otherwise make a notification sound. The catch here, however, is that you can’t control which notifications cause the LED to flash, so if you enable this, you’ll get a flashing LED for everything from calls to Facebook notifications.