Settings for What iPhone Looks Like, Sounds Like, and Reports

Who doesn’t want a bright, vibrant screen? Alas, the brightest screens exact a trade-off: Before you drag the brightness slider to the max, remember that brighter screens sap the life from your battery more quickly.

Tap the Auto-Brightness control so that it’s on. This control adjusts the screen according to the lighting conditions around the iPhone while being considerate of your battery.