iPhone X auto brightness doesn’t go to minimum

Discussion in 'iPhone' started by christarp, Nov 10, 2017.

  1. christarp macrumors 6502

    christarp

    Joined:
    Oct 29, 2013
    #1
    Hey guys, lately I’ve noticed something odd about auto brightness on my iPhone X, it doesn’t seem to go to the minimum brightness even when it’s pitch black in the room, it typically stays where it was last put. And yes, I do have auto brightness on in the settings. Anyone else have this oddity?
     
  2. Aston441 macrumors 65816

    Joined:
    Sep 16, 2014
    #2

    This has been my PITA issue since iOS 8.

    A few versions of iOS 7 turned down brightness correctly. It has been broken since 8.0

    This makes me nuts when using my phone for nav at night. Every time I drive under a street light, the brightness zooms up, and has to be turned down manually, over and over again.

    My iPhone 5, 5s, and 6s+ all behave the same.

    I can't believe the bug hasn't been quashed after all these years.
     
  3. myscrnnm macrumors 65816

    myscrnnm

    Joined:
    Sep 16, 2014
    Location:
    Seattle, WA
    #3
    It must not affect all users, as my 6 Plus running iOS 10 could go all the way down to the minimum on autobrightness.
     
  4. Aston441 macrumors 65816

    Joined:
    Sep 16, 2014
    #4

    It affects all users. I've tested other's iPhones.

    Try this: when it's dark out, and there is no street light over you, set to minimum brightness. While continuing using the phone and keeping the display on, walk under a street light. The brightness increases. While continuing to use the phone, walk back to the dark place you started. Does your phone drop back to minimum brightness where you set it? Nope. That's a bug.
     
  5. myscrnnm macrumors 65816

    myscrnnm

    Joined:
    Sep 16, 2014
    Location:
    Seattle, WA
    #5
    Mine does. I never said it wasn't a bug, just that it doesn't affect all phones.
     
  6. Aston441 macrumors 65816

    Joined:
    Sep 16, 2014
    #6
    You're the only one I've heard from that says that. I don't disbelieve you, but I'm curious if you get a chance to try the streetlight test above, when you get a chance, and report back here.
     
  7. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #7
    I thought this was on purpose because when on minimum brightness, the consequential inability for iOS to dim the screen further for a few seconds before it auto locks (like it does at all other brightness levels) makes for an unpleasant user experience where the screen just suddenly shuts off.
     
  8. myscrnnm macrumors 65816

    myscrnnm

    Joined:
    Sep 16, 2014
    Location:
    Seattle, WA
    #8
    I don't need to do the streetlight test because I was able to observe this phenomenon every night using my phone in bed. The bedroom is pitch black, and I'll be using my phone and check the brightness level to make sure it was as low as possible to reduce eye strain, and then I would turn on the lamp on the nightstand for whatever reason and set my phone down, and the brightness would increase, then when I got back in bed and started using the phone again you could actively see the brightness scale dip all the way back down after I turned off the lights.
     
  9. BrettDS macrumors 65816

    Joined:
    Nov 14, 2012
    Location:
    Orlando
    #9
    I believe that the auto brightness allows you to ‘customize’ it by manually changing the brightness. It then tries to work based on what you have manually set, so if you raise the brightness a bit from where it would normally be, then it will continue to keep it slightly brighter than it would otherwise do, including not dimming the screen all the way in pitch black.

    To ‘recalibrate’ it you can go into a pitch black room, turn auto brightness off, manually set the brightness to 0, then turn auto brightness back on. At this point it should raise when you take it out into the light and lower again to 0 when you go back into pitch black.

    However, if you manually adjust it again, it will try to adjust auto brightness based on your manual input and it may not go all the way to 0 in pitch black if it thinks that you want the screen slightly brighter than standard.
     
  10. Aston441 macrumors 65816

    Joined:
    Sep 16, 2014
    #10
    Interesting. I've tested six or seven phones and they all dip to ~one notch above minimum. I watch the slider move too. Hmm. I wonder what's going on that's different with yours. Are you running iOS 11? Did your phone ever display the behavior I'm describing?
     
  11. myscrnnm macrumors 65816

    myscrnnm

    Joined:
    Sep 16, 2014
    Location:
    Seattle, WA
    #11
    This was when it was running iOS 10 and older. I haven't used my 6 Plus since getting the X, and only updated to 11.1 because I wasn't sure if a backup made from an older version of iOS would work on the X. And as far as I can recall, it did not ever do that.
     
  12. Aston441 macrumors 65816

    Joined:
    Sep 16, 2014
    #12

    Maybe it's because you go from light to completely dark? I'll have to test a completely dark scenario when I get home.

    I've only tested in the outdoor urban/driving environment, which is not completely dark. Maybe that's where this bug pops up.
     
  13. christarp thread starter macrumors 6502

    christarp

    Joined:
    Oct 29, 2013
    #13
    Even when I wake the screen up in the middle of the night in bed (say at 3am) the brightness is maybe a little bit lower than where it was when I used it with the lights on hours ago, but it's never below 50%. That's the issue I'm running in to.

    The screen will brighten and dim in bright light / other transitions, but it will never dim below 50% for some odd reason, meaning checking the time in the middle of the night is a pretty bright affair.

    I just tested this. I turned off every light and made sure it was pitch black, and then reduced my brightness to all the way down (0%). Then I turned on a light and the brightness went back up (to say about 80%). After that, I turned the light back off, and put the phone to sleep. Waited about 10 minutes and unlocked the phone in pitch black once again. This time, the auto-brightness lowered the brightness, but not to the original setting it was in pitch black. It lowered it to about 50% which was still very bright in a pitch black room.

    So I just did this, and it worked! I always figured the auto-brightness would have full dynamic range, and that manually changing the brightness would merely override it for a certain period of time before going back to its full dynamic range.

    However, after doing the steps BrettDS mentioned, it looks like maybe there's a smaller range of values that auto-brightness operates at.
     

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12 November 10, 2017