Updated to iOS 6, Autobrightness no longer works.

My theory is the device has a little more trouble reading the ambient light when it comes to dimming because it sees the light reflecting from the display. By locking the device it gets a chance to read the light with the display off. That's just a theory :)

Are you sure its not dimming. It dims up much faster than it dims down. Open the brigtness setting with auto-brightness on and move the phone from sunlight to darkness (just discovered by the way, that covering up the sensor with your hand is not good enough - you actually need to put your phone in a dark place). You should find the slider moves itself to the left very slowly in dim light, and moves quickly to the right in bright light. Dose it do that?

Yep. At night the iPad screen is blinding since it has so much surface area... I gave it a chance to adjust in a dark room and tried locking also. Even a restart didn't help.

Sounds like a bug to me. Maybe give your device a proper turn off and turn on. If that still doesnt solve it pay the apple store a visit next time youre in town?

I'm assuming its a bug since others are also having the problem. And since I'm a Windows user I natively default to the reboot to fix option :) still didn't help. I imagine a bug fix will be out in a few weeks. Just gotta make sure that the engineers hear about it.

Haha yeah me too. By the way your theory about the dimming being slow because of the light relecting off the glass makes sense, because it explains why it dims if you move to a dark room, but not if you cover up the sensor with your hand. Light seems to be able to pass along the glass beneath my hand to reach the sensor so it wont dim.

Ok....this is odd...

My auto rightness is working at the moment? Same circumstances and settings as before. Totally dark room, press lock, press lock again and the screen is dimmed. Turn light on and it slowly increases like its supposed to.

Why it didn't do that last nigh??? All I've done since then is sync with iTunes and delete a few apps.......

I'm confused. Still no dimming without locking, but that's the way it's always been.

i have ipad and iphone and and they had this 'only to the right' autobrightness both. but suddenly after the upgrade for ios6 i've realised the 4s is working properly, brighting up and dimming the screen as it should be! unfortunately there is no such effect for the ipad.

looks like apple has revamped screen brightness software for iphone only (for iphone5). ios7 maybe?

I swore my auto brightness wasn't working. After multiple reboots and restore I about gave up. Then I put autobrightness on and put the slider all the way on the dimmest it could be. The slider began to move by itself. It seems that you can't set what type of auto you want it to be. If you move it to the middle it will stay there. But lower it all the way and the iPhone will control the brightness. Try it under a lamp and you see the slider begin to move.

I am having the same issue !!! After updating my iPhone 4S from 5.1.1 to IOS 6. My auto brightness is not working & if I change my iPhone brightness from lower to higher, it will automatically switch to low and vise versa. I turned off my iPhone also, I reset all settings in the setting menu but nothing works !!! When Apple gonna overcome this issue !!! 😟

which side?? can you actually see it can DIM?

I just tested on an iPad 2, the New iPad, and an iPhone 4S - It will only dim to the last and lowest setting you manually set.

Go into a dark room set it where you can read it and leave it alone.

You can go in the light and watch the brightness slider go up... turn it off and go back to a dark room and turn it back on. If you are quick enough you can get back to settings and watch the meter go all the way back to where you had manually set it - NO Furhter. So if you set it at 50% it want go below 50%.

I agree that is not how it worked in iOS 5, but that is how it seems to work in iOS 6

no it isn't. i went to the dark place and slide the brightness control to 20% approx. set auto on. then went to the sunlight - brightness went up. then went to the dark again - nothing happened, the screen keeps blinding me.

Did you "turn it off", before going back a dark place... or after you got there and turn it back on. Because if you did, we will have to disagree, because it works that way on every "new" iPad and iPhone 4S I have tried it on - 4 now.

Now I was mistaken - It does work that way on the iPad 2, worked the same way it did before.

Interestingly on the 4S and "new" iPad, if you have it on in a dark place and walk into a lighted place the bightness will incerease (and shows on the slider); however, walking back to the darken room the brightness will not decrease until the screen goes off.