iPhone XS Max XS Max brightness issues

joshen

macrumors regular
Original poster
May 27, 2015
115
304
Hi everyone,

In the past few days I noticed that the brightness of my iPhone XS Max randomly goes down to around 50% on its own, and returns to normal a while later. It stays like that even when I move the slider to anywhere above 50%. Auto-brightness is turned off.

Another issue I also noticed happening once was a major color shift. The dark greys in apps like YouTube and Reddit (dark mode), suddenly became a lot lighter in color. That issue was fixed after rebooting the device and hasn’t happened again since.

Could it be a software issue? Has it been happening to anyone else?
 

jermy4

macrumors demi-god
Jun 27, 2010
528
282
The brightness limitation is due to the temperature of the phone. It limits the brightness above a certain temp. Your other issue I have no idea.
 
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simplynando

macrumors 6502
Aug 15, 2016
329
285
Las Vegas, Nevada
I really hate this. It always does this to me. I live in Las Vegas and it's hot all the time. So as soon as I step outside and use my phone the brightness drops down to 50% and I hate it. It makes using my phone outdoors really hard. haha. But I finally figured out that it is related to the temp of the phone because once i'm inside for a while it slowly goes up to like 75% and then finally back up to 100% eventually.
 

Newtons Apple

Suspended
Mar 12, 2014
22,764
14,918
Jacksonville, Florida
Oh very interesting! It usually happens when I’m outdoors in hot weather with brightness set at 100%, so it makes sense.
I have not had mine dim but one time and it was near 100 degrees while outside. I had the brightness turned up so I could see and then noticed the screen dimmed. I had arrived back at the SUV so that was the end of it.
 

Jetcat3

macrumors 6502a
May 3, 2015
559
312
The Xs Max with an all white background pulls 4.2 watts at max brightness yielding 660 nits.

An 8 Plus is at 1.5 watts with 550 nits of brightness. The AMOLED panel on the Xs Max amazing uses 2.8 times more energy at max brightness and an all white background.
 

compwiz1202

macrumors 6502
May 20, 2010
408
74
Oh very interesting! It usually happens when I’m outdoors in hot weather with brightness set at 100%, so it makes sense.
Same happens with mine. I get the science but it is counterproductive. The one time I need full brightness is when the sun is shining bright.