I have auto-brightness on, so when I am somewhere bright the bightness of the screen increases but when I go away, somewhere less bright, the iPhone keeps the high brightness and doesn't decrease it ! Fix it apple !
It worked for me too but It maintains bright when it shouldn't !
Sensor works very well, both on 4S and 5 but people do not know how to set it correct.
1. You need to set slider on minimum brightness
2. Turn auto-brightness one ON/OFF and set it on ON, than it will adjust automaticly
"Auto-Brightness:
The auto-dim feature got significantly improved in iOS 6. The best improvement is brightness adjustment in the lock screen. Before, in a dark room, I would be blasted with the iPad or iPhone?s default brightness before sliding to unlock and having it dim down to match the room?s brightness. Now, from the moment the screen turns on, the brightness is appropriate.