Control Center on iOS 7 added a convenient method to use the flash on an iPhone as a flashlight. From any screen, including the lock screen, iOS 7 users are able to bring up Control Center and turn on the flashlight with just a tap. It was a welcome addition to the platform, albeit a small one, and eliminated the need for a third-party app to be installed on the device.
Often I have found myself using the flashlight long enough for my iPhone's screen to turn off. The process to turn the flashlight back off is the same as turning it on, requiring you to press the home or wake button, bring up Control Center, and then tap on the flashlight icon. Simple enough.
Thanks to a tip posted on Mac OS X Hints, the process to turn off the flashlight can be sped up to just one tap.
The next time you're using your iPhone as a torch, turn off the flashlight by tapping on the lock screen's camera icon. You'll find that the flashlight instantly turns off, with no further action needed on your part.