For those haven’t updated yet, please check your max brightness before updating and check if it’s less after the update. I think the max brightness is lower now. With DC dimming on and off (extra dim also off).
Edit: after a reboot the screen is bright again.
This issue with the backlight seems to be persistent. A reboot only temporarily solves it. To be more specific, the brightness is more or less only 2/3rd, no matter if you put the brightness level to 100%. This happens with or without DC dimming enabled.
If more people have this issue, then please let me know, then I at least know it’s not just my phone.
I can confirm this, have seen the issue on my phone, too. However I didn’t always need a reboot, sometimes it recovered from that issue in a different way that I’m not sure about yet. Might have been locking and unlocking again but then not always. It’s a little bit like the operator name that sometimes slides out of the screen and sometimes it doesn’t.
I’m currently a lot in the sun and had no issues with the screen being not bright enough, so I guess I’m not hit by this.
Is it similar to the FP4 issue?
As far as I can tell it’s not the same issue. I haven’t noticed a pattern yet.
Sure not the same in terms of heat/sun causing it, just similar in the behivour you notice, i.e. thr screen dims while the brightness slider is at max?
Yes, that’s right. But since this screen can go brighter, I can still read what’s on my screen. So 2/3 less brightness is still doable in most environments. For me anyway.
I also have an error with the screen brightness, explicitly not only with the automatic brightness control, but also with the manual one.
It sometimes happens that if you set the brightness all the way to maximum, the display brightness is just enough when the sun is not shining. When I restart the phone, everything is fine.
I created a topic for you and merged the comments from the latest update topic over.
At random the screen brightness of the fp5 is limited to about 50% of its actual capacity. This happens maybe once in 3 days, but it’s really random. A reboot fixes this issue. Recently I wasn’t able to scan a QR code for a package pickup due to this and had to reboot my phone. 1st world problems I suppose, but worth a look by FP. The issue is less of an annoyance as with the fp4, because the FP5 brightness capacity is higher. So about 50% of that is still doable most of the time. Will report it to FP support.
Isnt that the same?
https://forum.fairphone.com/t/fp5-screen-dimming-without-adaptive-brightness/103117?u=yvmuell
In some cases for me it helped to cover the light sensor and then uncover it again. Then the brightness would go up - unfortunately not always.
The topics address the same issue, indeed.
I mereged the topics
It’s indeed the same issue, I was looking for it but wasn’t able to find it. Thanks for merging it!
Now I found a way to get the brightness up that has worked every time I tried it:
If you find the brightness is low again, then turn off the screen, cover the light sensor while turning the screen back on. It’ll turn on with low brightness again but as soon as you uncover the light sensor the brightness will go up to where it should be.
Does anyone have a ticket open for that issue? Then you could pass this information on to them after you’ve checked if it works for you, too.
Thanks a lot. Works fine for me, too!
Rebooting the phone helped in my case, after the display was so dark that I saw literally nothing outside with max brightness and DC on or off and max. dim off. 
will try the light sensor work around next time it happened.
Yes, please try it. I’ve noticed that I don’t even have to turn off the display, I can just cover the light sensor for a few seconds without doing that, and then uncover it again and brightness will go up. With this it’s no real issue anymore for me.
Seems like the sensor doesn’t know its limits when it’s turned on. So it assumes that the brightness it sees at that moment is the lowest that it could ever see. When covering the sensor it realizes that it can still be darker and so it sets a new baseline and when uncovering it notices that the environment brightness has increased and so it’ll turn the display brighter - something like that…
@Martin_Anderseck i can confirm, workaround work for me, as you write previous “Off, Cover, On, Uncover”, before i use my method “in confusion/random change to min, max, auto on/off, min, max…” 
not try yet as you write latest “Cover,Uncover” only…
Where is the light sensor, and other sensors?