Apple Event: May 7th at 7 am PT
My iMac (Retina 5K, 27-inch, 2017) reduces brightness after a few seconds of inactivity (not completely black, so no screen shutdown or screensaver). I don't think this is normal? PRAM/SMC reset done.
iMac, OS X 10.11
Do you have automatically adjust brightness selected?
The opposite of this (sudden extreme brightness) happened with me but not my wife and we have identical 27" 2020 iMacs. My fix, until a MacOS came along that resolved it, was to put a piece of black tape over the camera. That worked, but was hardly a desirable fix.
Yes, I have automatically adjust brightness selected. What I do not understand with automatically adjust brightness, should this function adjust brightness constantly according to room levels, or is this kind of a screen saver? In my case it works like a screen saver; it dims after inactivity and reverts after activity.
Very interesting what you write about the experienced difference between 2 identical iMacs. In my case, I have the impression that it never happened until recently. I first thought it might be a latest MacOS feature (additional power saving) but that does not seem to be the case.
I did a hardware check on my iMac and everything was ok.
It's an adjustment based on ambient light levels, that's how covering the camera's aperture blocked it's action.
Everything was fine with my hardware too, but if I open the Display icon and then passed a flashlight beam on the camera then away, I could see the brightness slider response to increasing and decreasing light levels. I can still do that now ... kind of creepy. Try youre with a flashlight and see what happens.
Don't remember which upgrade or update fixed it, but I no longer have the problem.
So in your case it is not acting like a screensaver? In my case it is not based on ambient light levels, but it dims after let’s say 30secs of inactivity and reverts as soon as I move my mouse. Something which I remember to have seen on my MacBook but never on my iMac. It is like having a pre-screensaver before the screensaver kicks in. Like my OS would treat my iMac like it would be a battery-powered device.
I found the function; it is called "Automatically reduce brightness before the display goes to sleep". Looks like a function designed for MacBooks; it is weird that I have this now on my iMac. There is also no checkbox in the settings to disable it.
I have updated to MacOS 12.1. and I am currently no longer experiencing this behaviour. Looks at least for the moment as it has fixed it.
Definitely not a screen saver on any of our five Macs.
My iMac (Retina 5K, 27-inch, 2017) reduces brightness after a few seconds of inactivity (not completely black, so no screen shutdown or screensaver). I don't think this is normal? PRAM/SMC reset done.
