Using Your iPhone’s Flash
The iPhone has an LED (light-emitting diode) flash that controls pictures taken with the rear camera. Because no flash is associated with the front-facing camera on the 5s, 6, or 6 Plus, you won’t see the flash button when you’re using that camera.
You see a flash icon when you’re using the front camera on the 6s and 6s Plus. When the button is available, tap it to change the setting to On, Off, or Auto. It’s usually easiest to use the Auto setting, which lets the iPhone decide when it’s a good idea to fire up the flash.
The iPhone has not one but two rear flashes as part of a, um, flashy feature Apple refers to as True Tone flash. The two flashes — one white, one amber — work in tandem to match the flash to the ambient lighting in your shooting environment. The system determines the light intensity and which combination of the two flashes to fire off automatically, with more than 1,000 possible combinations, Apple says.
You don’t need to worry about any of this when you’re out taking pictures. Just turn the flash setting to On or leave it in Auto and trust True Tone flash to choose an appropriate combination. Although not every flash photo you take will be ready to hang in a museum, much less over your fireplace — hey, the photographer has to bear some responsibility.
The FaceTime camera on the 6s and 6s Plus also takes advantage of what Apple refers to as a Retina Flash. For just a moment, the Retina display on the phone brightens by three times with True Tone lighting to bolster those selfies you snap in dim settings, made possible by a custom display chip.