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The feature is nice, but doesn't work very well. I just have mine adjusted just right for day and night.

+x POS.
 
Okay guys, Im gonna give this a go at explaining since I've got it working perfectly. Basically, it's like this: the value that you slide the "Auto-Brightness" slider down to in Settings is the MINIMUM value your screen brightness will EVER allow itself to go. So if you are in a completely dark room, this is the screen brightness your phone will be. Then, if you walk out from that bright room into a lit hallway or something and give the phone 5 or so seconds, it will light up correspondingly (maybe not all the way to full). Then, if you walk from that hallway into the sun and give it 5 seconds, it will adjust automatically to full brightness. Unfortunately, I have not found this to work the other way around. Without sleeping the phone and then unlocking it, it will not go from a brighter screen (in a well lit place) to a dimmer screen (in pitch blackness for example). Hope this helps. Later.
 
Weird. Take it back.

I've seen this feature act so weird on so many phones I'm certain they won't do anything about it. I mean, unless they WANT to replace 1/3 of the phones out there. I just don't see it happening, so I never bothered.

Okay guys, Im gonna give this a go at explaining since I've got it working perfectly.

That all sounds good, but I've gotten opposite results on different phones that were set the same way.
 
Update: I went to the Apple store and a Genius told me that he has come across this problem many times before. He said he has never once owned or seen an iPhone or iPod that has a functioning auto-brightness. Another fellow Genius also confirmed that.

All he told me that hopefully Apple will come out with a patch to fix it. This doesn't really help anyone, but I hope it's an explanation for those who are also wondering.
 
This is my 2nd iPhone and on both of them, I have felt that the brightness only adjusts a very small amount up and down from where it's set. It definitely does not adjust enough, especially turning it on in a dark room after waking up!
 
Auto-Brightness works fine for me, you just have to know how it works. (I'm not saying you don't know how it works, but you may be overlooking something)

It will get brighter while using it, but it won't get darker. You have to put it in sleep, then wake it up for it to turn down.

Make sure when you're waking it, the light from the screen isn't reflecting on anything. When you have it on the lock screen, it will display it at the highest brightness that you're setting allows. If this gets reflected on something, and the phone sees it, it could interpret it as a lighter setting than you're in, and will turn the brightness up higher.

Also, even if you're in a completely dark room, if the brightness is set to full, it won't go down to the lowest setting.
 
my 3g doesn't work at all... (which is weird because the proximity feature works all the time... surely if one sensors works flawlessly, the others aren't crap?)

I'm in a pitch black room (no lights on at night) ... set the brightness all the way down to 5% or whatever the lowest is, lock the telephone.

Then I turn the brightness of my macbook pro all the way up... face the iphone towards the screen, unlock it, and let it sit for like 30 seconds and it NEVER budges off of the zero mark.

it's bull crap...Why does apple screw up so many simple things on such an advanced device?
 
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