Database Develop

[Q] Light Sensor Not Working?

Someone correct me if I am wrong but shouldn't enabling the option of "Automatic brightness adjustment" under the brightness menu in sounds and display enable the light sensor to adjust the brightness of the LCD based on ambient lighting? I notice no difference with my brightness and it is always one static level. I've tried putting it up to different lights, taking it outside, etc and it doesn't automatically adjust. I couldn't find anything in a search for this... does anyone else have this problem?

I have this problem as well. What firmware are you running and do you have any mods or sre or anything?
Sent from my SAMSUNG-SGH-I897 using XDA App

I'm just running stock firmware rooted, I'm going to flash to some kind of rom eventually but just haven't had the time
Are there any roms that this option is confirmed working?

Mine is stock and seems to work just fine. It changes brightness as I move through the office between dark reading rooms and bright conference rooms.
I'm not a big fan of that feature in any of my phones. I prefer to have a constant bright screen, but I haven't bothered turning it off yet for some reason.

Weird how mine doesn't work.. I just waste battery life while I am in the office with the phone and wish it would auto adjust. I'm trying the beautiful brightness widget but I find it tedious to have to micro manage my brightness before going outside

Have you installed any type of screen protector that requires the use of water to apply? I'm wondering if that's what happened to mine.
Sent from my SAMSUNG-SGH-I897 using XDA App

Auto brightness doesn't seem to be working too well in JH7 for me. Keeps the brightness all the way down in my lit up room. Worked best on the original JF6.

I have seen my screen change brightness a few times with the automatic setting, but I generally keep it on the lowest brightness to save battery. I'm running the stock firmware.
My biggest problem with the auto brightness is that the dynamic range isn't wide enough. Even in direct sunlight, it doesn't bump up to maximum brightness. The high should be higher, and the low should be loooower.
Sent from my SAMSUNG-SGH-I897 using XDA App

No screen protector, just a Body Guards case
Sent from my SAMSUNG-SGH-I897 using XDA App

I noticed the same...no change in brightness when "auto" is selected. From day 1. I keep my brightness pretty low to save battery life, so it wasn't a deal breaker. Would be nice if it worked though.
Sent from my SAMSUNG-SGH-I897 using XDA App

Auto Brightness problems?

Auto brightness seems to behave very unpredictably--when I wake my phone and unlock/use it, it will remain at dimmest setting (too dim), and will seemingly randomly move to a more appropriate brightness (not with intense activity, it's really random), and will again randomly revert to dim setting (not with stoppage of activity).
Is auto brightness messed up with android or the note, and how can I fix it? Just set a manual brightness level?
Running cassie x lite rom and latest franco kernel btw.

No advice about this anyone?

Automatic brightness issue
Hello Friends, I have a similar problem as the OP, octavian90.
For my Galaxy Note, following the sequence below,
Applications > Settings > Display > Brightness
By default the slider for Automatic brightness is towards the middle/centre.
I have unchecked Automatic brightness and calibrated the slider to the extreme left.
I have come across the following strange observations -
1] When I unplug my device after charging, the slider resets to the default level.
2] After I recalibrate it to the extreme left once again and make a phone (voice) call, the slider resets to the default level over again.
Is this normal behaviour or does my device actually have a problem? I am very confused and worried. The device is not even a month old.
Eagerly awaiting your expertise. Thank you octavian90 for initiating this topic.

Friends, awaiting your much needed replies to my queries above.

Have you disabled the screen saver or what its called that adjust the brightness automaticly.? Works like a auto brightness but it can adjust some things brighter and some dimmer eaven on same light....

I just checked my settings and the have the slider all the way to the right because last time I manually adjusted brightness for reading in full daylight. It is currently on automatic brightness (I prefer that setting and don't find it changes too often or too laggy)
I just then manually adjusted slider to about 20% from left while on USB charge then turned automatic back on again. I then removed charger and it still shows automatic and slider about 20% from left.
Could be a ROM/Kernel issue? I am using Rocket ROM with Franco Kernel.

I don't think the position of the slider matters when backlight is set to auto. Or does it?
Sent from my rooted Galaxy Note using XDA Premium App

altae said:
I don't think the position of the slider matters when backlight is set to auto. Or does it?
Sent from my rooted Galaxy Note using XDA Premium App
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Click to collapse
No it doesn't matter when on autobrightness. But it should remember the last manual setting chosen so not sure what is causing that glitch.

Hm never really paid attention to the behaviour of the slider. I will take a look and report back how mine works.
Sent from my rooted Galaxy Note using XDA Premium App

What I found out: On my device the position of the slider before activating auto mode is completely irrelevant because as soon as I activate the auto mode the slider is reset to its middle position.
Sent from my rooted Galaxy Note using XDA Premium App

Interesting - just turned autobrightness of and you are right - slider went to the middle. Must be by design then. Problem solved

SoonHD2 said:
Have you disabled the screen saver or what its called that adjust the brightness automaticly.? Works like a auto brightness but it can adjust some things brighter and some dimmer eaven on same light....
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Click to collapse
Sorry SoonHD2, I did not understand what you meant. I am confused with the screensaver part you stated.
A humble request for an explanation, if required. Thank you.
altae said:
What I found out: On my device the position of the slider before activating auto mode is completely irrelevant because as soon as I activate the auto mode the slider is reset to its middle position.
Click to expand...
Click to collapse
This happens with my Galaxy Note as well. Thus, it seems like it is meant to be this way.
I will keep an eye on this and report if and when the Auto brightness slider acts differently.

Brightness, no more Auto

I haven't used Lollipop at all yet, just picked up the N6 yesterday. Autobrightness is gone, now they want you to slide around the bar to however you want it with adaptive brightness? now how does this work? lets say I set it to full brightness and enable adaptive, itll use anywhere from 0-100%? is the bar just to cap it somewhere so it doesn't exceed? if so what do you have yours set to? Whats a good way to do this all and avoid image burn, ha. which I Heard is kinda a big deal

imablackhat said:
I haven't used Lollipop at all yet, just picked up the N6 yesterday. Autobrightness is gone, now they want you to slide around the bar to however you want it with adaptive brightness? now how does this work? lets say I set it to full brightness and enable adaptive, itll use anywhere from 0-100%? is the bar just to cap it somewhere so it doesn't exceed? if so what do you have yours set to? Whats a good way to do this all and avoid image burn, ha. which I Heard is kinda a big deal
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Click to collapse
That's exactly how adaptive brightness works. I have my slider set around 25-30%. I change it if I need more outdoors.

imablackhat said:
I haven't used Lollipop at all yet, just picked up the N6 yesterday. Autobrightness is gone, now they want you to slide around the bar to however you want it with adaptive brightness? now how does this work? lets say I set it to full brightness and enable adaptive, itll use anywhere from 0-100%? is the bar just to cap it somewhere so it doesn't exceed? if so what do you have yours set to? Whats a good way to do this all and avoid image burn, ha. which I Heard is kinda a big deal
Click to expand...
Click to collapse
This is how I understand it and how I believe it works.
With adaptive brightness OFF, you have your brightness slider in the pulldown that goes from ~5% to 100%. This slider set value will remain until you manually change it. Easy enough.
With adaptive brightness ON, you have that same slider in the pulldown that goes from 0% to 100%. Your brightness will change automagically dependent upon ambient light. Look at it as "minimum automated brightness level"
Some tips. Your screen can get darker with adaptive ON and slider all the way down than with adaptive OFF and slider all the way down. Unless in very bright ambient light, your screen can get brighter with adaptive OFF and slider all the way up. Hence, in full sunlight, the peak brightness of the screen is the same with adaptive either ON or OFF and slider all the way up.
I admit its confusing and it frustrated me at first, but I think its excellent and works much better than auto brightness on any other phone or older android OS I've ever used.
As far as burn in (or the more often occurring image retention), well its an amoled, it's susceptible. Just be smart about it and don't display the same static image/s for hours on end.

jbdan said:
Look at it as "minimum automated brightness level"
Click to expand...
Click to collapse
I used to think that but after testing, it seems more complicated than that.. It also looks like to may apply a "range" using the slider, but its more complicated than that too.
The closest thing I can think of is it increases the sensitivity or effectiveness of the adaptive brightness.
Have a look at our tests here, maybe you can do some testing and develop our initial findings.
http://forum.xda-developers.com/galaxy-s3/general/thread-t1889453/post60222532

I'd love to set it to an exact percentage cuz I'm ocd that's why I hate the slider. How do I really know it's at 25%
Sent from my Nexus 6 using XDA Free mobile app

imablackhat said:
I'd love to set it to an exact percentage cuz I'm ocd that's why I hate the slider. How do I really know it's at 25%
Sent from my Nexus 6 using XDA Free mobile app
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Click to collapse
Yeah but once you know 25% is 63.75 on the brightness scale and brightness can only register full numbers, you're day is blown anyway.

rootSU said:
I used to think that but after testing, it seems more complicated than that.. It also looks like to may apply a "range" using the slider, but its more complicated than that too.
The closest thing I can think of is it increases the sensitivity or effectiveness of the adaptive brightness.
Have a look at our tests here, maybe you can do some testing and develop our initial findings.
http://forum.xda-developers.com/galaxy-s3/general/thread-t1889453/post60222532
Click to expand...
Click to collapse
I think you nailed it better than I did in my explanation with your statement "increases the sensitivity or effectiveness of the adaptive brightness".
My explanation was as simple as I could write it. I especially like the word "range". Thanks for the link I'll check it out :thumbup:

So is it true if its set half way if the sun hits it that it can use 100%. What do you guys have it set to? I liked the auto brightness ?
Sent from my Nexus 6 using XDA Free mobile app

imablackhat said:
So is it true if its set half way if the sun hits it that it can use 100%. What do you guys have it set to? I liked the auto brightness ?
Sent from my Nexus 6 using XDA Free mobile app
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Click to collapse
Yes if the sun, or even very bright ambient light hits the sensor, the display will go to 100% full brightness with adaptive ON. At least it does with mine (to my aging eyes). I leave mine at about 50% adaptive ON. I like it too

imablackhat said:
So is it true if its set half way if the sun hits it that it can use 100%. What do you guys have it set to? I liked the auto brightness ?
Sent from my Nexus 6 using XDA Free mobile app
Click to expand...
Click to collapse
I use manual.brightness.

For everyone testing display settings have a look at 'Pixel battery saver' in the play store.
The app switches patterns of pixels off and saves energy.
Note.
Because this kind of apps are switching pixels off, it is possible that ticking buttons will not work.
But there is an option to turn it off, and several levels of settings.

The note 8 sun mode kicks in even with auto brightness turned off

Ok guys so I need to know if there is a sensor issue with my phone .I don't use auto brightness no more because if you go in the sun the brightness overrides itself to brighter than max brightness and it is the reason why I've had burn in 4 times so far and had to get the screen replaced. But I've also noticed that with auto brightness off but you have the brightness maxed out and go in the sun or shine an led torch at the sensor the screen will kick up to override max brightness sun mode out like when using auto brightness. Is this normal behaviour. Can anyone test this fpr me please .only 6 months left of warranty left
So if this is a feature its stupid ,and make sure you never put your phone on max brightness in manual or autobrightness if out side and it's sunny as it will kick in and cause screen burn .
I've factory reset it and cleared cashe still the screen in manual mode if maxed out in the sun with the brightness maxed out will auto ride to super max brightness mode .im on the oreo uk fm
Phone is uk unlocked note 8.

Anyone? I see lots of views no replys I'm sure everyone that view this thread owns a note 8?

OK lol thanks for the great respone guys smh this place sucks :good:

haircut123 said:
OK lol thanks for the great respone guys smh this place sucks :good:
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Click to collapse
No, this place does not , if you do not get any response , it means nobody has something useful to share, beeing rude will gain you a ban

Maybe your the only person that has this error, so no one has any advice to give other than to factory reset (which you all ready done).
Most people has moved on to other phones. So you'll have to be patient. I say is take it to the Samsung store and see if it is covered under warranty.

I'm not the only person all note 8s do this i think but nobody in this thread owns a note 8 or 9 other than me because they both do it. On both my phones.its a terrible feature as it will cause burn in.if you want to be able to see the screen outside in the sun

So i've been using auto brightness for 2 years, i don't have any burned screen. Last week I've been using phone on sun, taking a lot of pictures (brightness set to auto, on camera app its option to set it to max bright) and still no burnout. I think you should say your problem to guy who will accept your warranty next time

Well this is good to know just went to the sammy service centre and tested the phones they had there with my led torch and they all do it including the s9 plus .so it maybe always was like that or it's been added into a fw.

haircut123 said:
Well this is good to know just went to the sammy service centre and tested the phones they had there with my led torch and they all do it including the s9 plus .so it maybe always was like that or it's been added into a fw.
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Click to collapse
I will add that friend have a s8, his screen is good. Also another friend had note 8 and now note 9, always autobrightness on, no problems so far.

I have a little experiment
1st, I set auto brightness on, turn on a torch on the sensor, brightness go to max, then turn it off, and brightness go to middle (room light on)
2nd, set the auto brightness off, slide the brightness to minimum, turn on the torch to sensor, and brightness remain to minimum, nothing change
So I assume maybe it's a software feature I don't have, you can check with your friend running the same firmware, or you can check using *#0*# on keypad, click on sensor, look for light sensor, and do a simple test, see how much lux you have when you're on direct sunlight, or in a room, then you can flip your phone down / reverse the light source, the lux sensor must be read it on continuous count, as you flip your phone, the number will get decrease
I hope you understand what I am saying, because English is not my native language

ahmadddea said:
I have a little experiment
1st, I set auto brightness on, turn on a torch on the sensor, brightness go to max, then turn it off, and brightness go to middle (room light on)
2nd, set the auto brightness off, slide the brightness to minimum, turn on the torch to sensor, and brightness remain to minimum, nothing change
So I assume maybe it's a software feature I don't have, you can check with your friend running the same firmware, or you can check using *#0*# on keypad, click on sensor, look for light sensor, and do a simple test, see how much lux you have when you're on direct sunlight, or in a room, then you can flip your phone down / reverse the light source, the lux sensor must be read it on continuous count, as you flip your phone, the number will get decrease
I hope you understand what I am saying, because English is not my native language
Click to expand...
Click to collapse
You did the test wrong friend you need to turn off auto brightness and slide the brightness slider to max brightness it must be fully maxed .then shine led torch at the sensor then the brightness overide kicks in and goes even brighter just like In auto brightness mode.but if the slide is not fully maxed it won't do it

haircut123 said:
I'm not the only person all note 8s do this i think but nobody in this thread owns a note 8 or 9 other than me because they both do it. On both my phones.its a terrible feature as it will cause burn in.if you want to be able to see the screen outside in the sun
Click to expand...
Click to collapse
haircut123 said:
Well this is good to know just went to the sammy service centre and tested the phones they had there with my led torch and they all do it including the s9 plus .so it maybe always was like that or it's been added into a fw.
Click to expand...
Click to collapse
Interesting you mentioned all devices do this before you went to the service centre and confirmed it. That admission renders your entire post pointless. If all the devices does this, it means it's not a fault on your sensors or anything on your side, and it means it's indeed just a feature.

Max_Terrible said:
Interesting you mentioned all devices do this before you went to the service centre and confirmed it. That admission renders your entire post pointless. If all the devices does this, it means it's not a fault on your sensors or anything on your side, and it means it's indeed just a feature.
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Click to collapse
I said imo that all devices have this issue. Because bothe my note 8 amd 9 have the same issue .and i found a thread on reddid where 2 others also had the same issue.its not a feature because it can damage the screen it must be a software bug that Sammy need to fix

haircut123 said:
You did the test wrong friend you need to turn off auto brightness and slide the brightness slider to max brightness it must be fully maxed .then shine led torch at the sensor then the brightness overide kicks in and goes even brighter just like In auto brightness mode.but if the slide is not fully maxed it won't do it
Click to expand...
Click to collapse
Ah I see, after doing that, I found out that the screen goes brighter and the colors seem to be fade out
Maybe it will help us to watch better when we got under direct sunlight (I think it's not a bug)
But in real life usage, I have my adaptive brightness turn on, then when I think it's too much bright at the moment, I will manually adjust it to my desire brightness
So that the system will learn the pattern and will apply automatically next time I had the same condition

Doesn't do that with mine and I live in Hong Kong.

Auto brightness working well for you guys?

I noticed that on my S10e, auto brightness doesnt work as well as it did on my Note 9.
Sometimes I have to manually turn down my brightness if I turn off the lights in my bedroom for example. Or if i turn on the lights, brightness stays on the same level. But if i turn off my phone display then turn it back on, the brightness is suddenly changed.
How well does it work for you guys?

destz0r said:
I noticed that on my S10e, auto brightness doesnt work as well as it did on my Note 9.
Sometimes I have to manually turn down my brightness if I turn off the lights in my bedroom for example. Or if i turn on the lights, brightness stays on the same level. But if i turn off my phone display then turn it back on, the brightness is suddenly changed.
How well does it work for you guys?
Click to expand...
Click to collapse
I have noticed that my S10e is slow to respond to ambient lighting

I have an S10 and to be honest it's hard to say if auto brightness is working how it should. Coming from an LG V30 this phone's display is significantly brighter and especially more apparent when using it in the dark. Even the darkest setting is too bright. I always check the level to make sure auto brightness is working as it should and I guess it is? Either that or it's stuck.

my only comment is that in totally dark room it does not go all the way down , it stays a little bit brighter than normal and than my old iphone x
talking about the s10+

Mohamad Gahed said:
my only comment is that in totally dark room it does not go all the way down , it stays a little bit brighter than normal and than my old iphone x
talking about the s10+
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Click to collapse
yeah same here, and the strange thing is that on my Samsung Note 9 & Samsung S7 it actually used to go all the way down in a totally dark room, but on this phone it doesnt for some reason..

It can take a bit for Adaptive brightness to learn what your favorite settings are like.

Yes, same here, I have s10 and in the dark auto brightness is near to half. Wtf?! I tried to calibrate, no chance. For sure this is a bug. If you go in *#0*# you will see it s writing uncalibrate light sensor

Devhux said:
It can take a bit for Adaptive brightness to learn what your favorite settings are like.
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Click to collapse
nah, on my Note 9 & S7 it worked as it should on the first day i got those phones
there clearly is a problem with adaptive brightness on the S10, anyone with the S10 who had another samsung phone previously will notice that

no, the auto brightness is trash. it sucks. it never gets bright enough even tho i've made adjustments literally daily. it sucks.

Charkatak said:
I have noticed that my S10e is slow to respond to ambient lighting
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Click to collapse
Yup. Same here. Maybe software update will fix this soon.
Even with factory reset it still happened.
Sent from my SM-G970U1 using Tapatalk

x1tymez said:
Yup. Same here. Maybe software update will fix this soon.
Even with factory reset it still happened.
Sent from my SM-G970U1 using Tapatalk
Click to expand...
Click to collapse
I too did factory reset...at least we have tried
Different topic: I will wait for T-Mobile firmware one more day and may possibly return the device back to Samsung and keep my Pixel 2

Charkatak said:
I too did factory reset...at least we have tried
Different topic: I will wait for T-Mobile firmware one more day and may possibly return the device back to Samsung and keep my Pixel 2
Click to expand...
Click to collapse
I got my first update on unlocked version. Why return?
Sent from my SM-G970U1 using Tapatalk

x1tymez said:
I got my first update on unlocked version. Why return?
Sent from my SM-G970U1 using Tapatalk
Click to expand...
Click to collapse
First reason: I want some T-Mobile features what unlocked doesn't provide natively and may require an extra app to function, but if before return window closes, I would be able to find a 100% firmware that would work, then I may not return the device.
Second reason: I don't like the fingerprint on S10e and maybe it is somehow better than S10's implementation, I still have to be more precise than Pixel 2 and other which had the sensor on the back.

Charkatak said:
First reason: I want some T-Mobile features what unlocked doesn't provide natively and may require an extra app to function, but if before return window closes, I would be able to find a 100% firmware that would work, then I may not return the device.
Second reason: I don't like the fingerprint on S10e and maybe it is somehow better than S10's implementation, I still have to be more precise than Pixel 2 and other which had the sensor on the back.
Click to expand...
Click to collapse
Interesting. I came from OnePlus 6t, the in displayed scanner suck kiwi balls. Everytime you switch screen protector you needed to rescan your finger. Lol.
Sent from my SM-G970U1 using Tapatalk

x1tymez said:
Interesting. I came from OnePlus 6t, the in displayed scanner suck kiwi balls. Everytime you switch screen protector you needed to rescan your finger. Lol.
Sent from my SM-G970U1 using Tapatalk
Click to expand...
Click to collapse
Oh, that is not convenient at all. I think the manufacturers are pushing their limits to please customers with new designs/features which in reality hurt the quality of the devices we pay for

I have the S10 plus and the auto brightness seems to be functioning fine. Occasionally in the dark I get thrown off with how bright this screen is. The brightness setting does decrease significantly in the dark but when viewing something with a mostly white background, I have to squint until my pupils constrict to a point where my retinas aren't getting torched. In brighter environments, the brightness level seems to increase accordingly.

Hi guys,
I came across an article about this issue from Aman Jain (Valuetalk) : https://www.valuewalk.com/2019/04/galaxy-s10-auto-brightness-no-issue/amp/
Facing Issues With Galaxy S10 Auto Brightness? Do This
Aman Jain Aman Jain
April 3, 2019 11:42 am
Samsung Galaxy Note 10E
rieo / Pixabay
Galaxy S10 auto brightness
rieo / Pixabay
We have already covered the issues with the proximity sensor in the Samsung Galaxy S10. Now, it appears, one more sensor in the Galaxy S10 is not working as it should. Several users are complaining that the Galaxy S10 auto brightness or the ambient light sensor is not working perfectly.
Galaxy S10 auto brightness – what’s the issue?
Affected users have raised the issue on social platforms and Samsung’s product forums (first spotted by tech site PiunikaWeb). Users complained that the brightness level does not automatically come down in low light. So, they have had to do it manually, but it remains at the set level even when the light is good.
“Sometimes I have to manually turn down my brightness if I turn off the lights in my bedroom for example. Or if i turn on the lights, brightness stays on the same level. But if i turn off my phone display then turn it back on, the brightness is suddenly changed,” one user said.
Further, users also say that with adaptive brightness turned on, the screen goes dark when facing the sun. “White highlights are bright blue, and all colors are distorted. It’s unusable. Spin back around or go into the shade, and the screen comes back to normal,” one user said on Reddit.
Users say that this was not the case with the Galaxy S9, where the auto brightness feature worked perfectly. One user even claims that the Galaxy S10 doesn’t even have a light sensor, instead, maybe there is some in-display sensor that needs a software fix.
“..even if you put your finger on the front camera the auto brightness still moves …..also if you acces this *#0*# you cannot find the light sensor because it’s not there like old samsung phones,” one user said on Samsung’s product forum.
Adaptive brightness to blame
Several users believe that the adaptive brightness is to blame here, and so they have turned it off. However, turning it off is not a solution, and many users agree to that.
“This is a huge problem, and should not be happening on a new phone. The adaptive brightness is a major feature of the phone, and simply turning it off isn’t an option as far as I’m concerned,” one Reddit user said.
It must be noted that Adaptive Brightness came with Android 9. It is an AI based feature that gets better with time. Meaning, it would learn from the interactions that users make with the screen brightness slider, and over time, it would customize the brightness automatically to meet the users’ needs.
Google says that in its testing for Adaptive Brightness, it found that half the test users made fewer adjustments to the slider after a week of using the Adaptive Brightness.
Not an issue, give it some time
Based on Google’s explanation, it seems, users need to give some more time for their phones to adapt to the Adaptive Brightness. Even Samsung’s explanation of the issue with the Galaxy S10 auto brightness is somewhat similar.
“From Android P, a user’s brightness setting pattern is learned, and when the user sets a specific brightness the automatic brightness is controlled to be closer to that specific brightness…… However, when you set the brightness, the brightness can be applied immediately in the short term. If more than 30 seconds after the screen is turned off and the ambient light environment changes by more than 60%, this short term setting brightness will return to the light that was relearned,” Samsung developers say.
Additionally, developers say that users can reset the brightness curve to start the learning process again. To do this, go to Settings – Apps – Show system apps – Device Health Service – Storage – Manage Storage – reset Adaptive Brightness.
All this explanation from Samsung developers and Google could mean that the complaints from users about the Galaxy S10 auto brightness are valid, but it still is not an issue. Things will get better with time as AI learns more about users’ preferences.
Though it is not a bug, affected users do not seem very satisfied as they still have to live with inferior quality images (even if for some time until AI applies the learning).
“Not sure it’s a error to be replicated per se. It’s just an inferior looking quality of image. They will have to make the comparison to see the very obvious difference,” one user said.
ValueWalk
FYI : the brightness sensor is under the screen like the proxity sensor, located bellow the wifi / network icon. It's visible at sun light.

inkortage said:
FYI : the brightness sensor is under the screen like the proxity sensor, located bellow the wifi / network icon. It's visible at sun light.
Click to expand...
Click to collapse
There are actually two light sensors: front and back of the phone.

Unlock the device without pressing the power button and only by placing your fingerprint on the sensor.
The light sensor starts checking the environment light only in this situation