The flash on your smartphone (or any camera, including that really expensive DSLR you bought that’s still set to “Auto”) is only practical in close quarters. It can only illuminate subjects about five feet away, or 10 feet if you really splurged on a nice camera. Unless you’re in the very front row of the concert and you can smell the last meal the lead singer consumed, all the flash does is light up the back of the head of the person in front of you. In fact, by using the flash, you’re actually degrading the photo of the subject you’re trying to capture. The band on stage will be a dim blur of color in the background.