I have an iPhone 4S and auto brightness was always working until I installed beta 1. All the updates have not fixed it for me. Hard resets, nothing. Is it a hardware issue? Like I said, working all the time before iOS 7, since then, its just not worked. Even on my iPad mini, its not working. Anyone else got this or know why its doing it? Is it because its in a beta and not optimized despite being an integral part of the OS?