Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

gmanist1000

macrumors 68030
Original poster
Sep 22, 2009
2,884
937
Why does auto-brightness always incerease the brightness when needed... But never decreases the brightness?

For instance, I unlock my iPhone in a dark room, and then walk into a well lit room. The iPhone will automatically increase the brightness to a perfect setting.

But, if I the iPhone is already on and I walk from a well lit room, to a dark room, it stays very bright.

Why doesn't it turn the brightness down automatically? I've always wondered this.
 
I'm pretty sure it does? I find that when I move from a well-lit room, in to a dark room, the brightness lowers... sometimes I have to manually turn it up.
 
I'm pretty sure it does? I find that when I move from a well-lit room, in to a dark room, the brightness lowers... sometimes I have to manually turn it up.

The only way my display will darken is if I lock it, and unlock it. Same with my iPad. BTW I have the setting at about 50% Auto-Brightness ON.
 
I'm pretty sure it does? I find that when I move from a well-lit room, in to a dark room, the brightness lowers... sometimes I have to manually turn it up.

I see mine darken too when I go from a brightly lit room to a darker one. I find Auto Brightness works for me without any intervention.
 
I hate auto-brightness. When I buy an iPhone, I turn it off. It's one of the first things I do.
 
I see mine darken too when I go from a brightly lit room to a darker one. I find Auto Brightness works for me without any intervention.

That's really strange that mine doesn't do it, on both my iPad and iPhone. I'm curious, what do you have the brightness toggle set at? Wondering if that makes any difference.
 
That's really strange that mine doesn't do it, on both my iPad and iPhone. I'm curious, what do you have the brightness toggle set at? Wondering if that makes any difference.

I have the brightness set in line with the last S in the word brightness.:)
 
Mine decreases as well but it seems like it takes longer then it does to brighten. Might be my imagination though.
 
x 1000

Mines does too, mabey your case blocking the sensor?

Strange... I have no case on either my iPhone or iPad, yet it doesn't dim the screen. Maybe the new 5.1.1 software fixed it. Let me go test this again...

EDIT: Just tested it again. Still doesn't auto-dim on iPad or iPhone. Brightness set at 50% Auto-Brightness ON.
 
Strange... I have no case on either my iPhone or iPad, yet it doesn't dim the screen. Maybe the new 5.1.1 software fixed it. Let me go test this again...

EDIT: Just tested it again. Still doesn't auto-dim on iPad or iPhone. Brightness set at 50% Auto-Brightness ON.

My iPhone 4 and iPad 3 have never auto dimmed. And my previous iPhone 4, iPhone 3GS and first generation iPad didn't auto dimm as well.
 
Mine doesn't decrese, just increases. It's really annoying. I've no idea why it doesn't auto-dim - it would seem so obvious to do.

Yeah, this is interesting. Many people here says theirs auto-dims, but some of us say theirs never auto-dims. Hmmm...

----------

My iPhone 4 and iPad 3 have never auto dimmed. And my previous iPhone 4, iPhone 3GS and first generation iPad didn't auto dimm as well.

I don't remember my previous iPad 2, and iPhone 3G auto-dimming either.
 
The only way my display will darken is if I lock it, and unlock it. Same with my iPad. BTW I have the setting at about 50% Auto-Brightness ON.
Then it is working.

When you first turn on the iPhone it does not engage auto brightness till it is unlocked. So the fact that you see it dimming after unlocking is because the room was dark enough for it to dim.

But it is not perfect....

Once auto brightness has brightened the LCD it stays there. It will not dim it again. Walk into a closet with the iPhone and close door with the closet's light off. In complete darkness it will dim the most. Now turn on the light and watch it brighten. Turn off the light and it will not dim again. Try it.



Michael
 
I can't find it right now but according to apple it supposed to auto brighten but not dim. There was a reason but it wasn't that good. It's supposed to happen after a sleep.

I'll check my iPhone 4S and iPad 2 when I get home.

The reason I look this up before is because I noticed on my friends iPhone 4 and at the time my razr did auto dim and we were researching if it was normal or not.
 
I agree. Getting OT a bit here, but Apple really needs to implement the "Brightness Feature" on the multitask volume setting (Double Home + Scroll left twice, under the volume). :)
 
Then it is working.

When you first turn on the iPhone it does not engage auto brightness till it is unlocked. So the fact that you see it dimming after unlocking is because the room was dark enough for it to dim.

But it is not perfect....

Once auto brightness has brightened the LCD it stays there. It will not dim it again. Walk into a closet with the iPhone and close door with the closet's light off. In complete darkness it will dim the most. Now turn on the light and watch it brighten. Turn off the light and it will not dim again. Try it.


Michael

Yes, it does work when I lock and unlock it in a dark room. However, shouldn't it darken the display when it is already bright and I move into a dark room? Because mine doesn't.
 
Btw I haven't tested mine yet but now I think about it, it was kind of annoying on my Razr and Android tablet. Seemed a little too aggressive. That might be the reason right there.

If you think about it. If its dim and you walk into the sun the phone is unusable however if it's bright and you go into a dark area it's just a little too bright but works just fine.
 
Yes, it does work when I lock and unlock it in a dark room. However, shouldn't it darken the display when it is already bright and I move into a dark room? Because mine doesn't.
It will.

But if it has brightened the LCD it stays there. I'm confident this is the behavior you are seeing. Try the test described, being sure to start out with the iPhone locked (locking it resets auto brightness).

Even though it is strange that it works this way, there was likely some thought behind it. I had an old PDA with auto brightness did go both up and down always. For some reason it drove me crazy and I had to turn that off. I remember when I got my iPhone it was refreshing to see it actually work right.

But on the other hand there are probably some whose usage pattern causes them to run into the "won't dim" situation more than others. It could be something like longer auto-lock settings, since auto brightness resets every time the iPhone locks.

As for me, I never notice it. I just leave it on and it works well for me. I know it is working as I can see it brighten when I turn it off. You might ask, then why not lower brightness level and turn off auto brightness? Well then it won't increase brightness when I am out in bright sun and need to use it. Conversely, it won't dim it when I awake in the morning to check on some things with my iPhone (room still dim).




Michael
 
Last edited:
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.