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LG Ultrafine 4K Ambient Light Sensor
- Thread starter anferro
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I did find this but it may be old information.
Or it may not be recognizing the sensor on the display (if it even has one)?
How to Automatically Adjust Brightness Based on Ambient Light
Macs with built-in ambient light sensors can monitor the light level nearby and automatically adjust the display’s brightness level to be suitable. This means making the display brighter when it’s bright near you, and making the screen dimmer when you’re in the dark.
To find this option, open the System Preferences window from the Apple menu and select “Displays.” Enable “Automatically adjust brightness” and your Mac will use the ambient light sensor to automatically adjust the brightness. Disable this option and your Mac won’t do this.
If you don’t see this option here at all, your Mac doesn’t have an ambient light sensor.
Despite the name, this option only applies to the ambient light sensor. Even if you disable the “Automatically adjust brightness” option, your Mac will still dim the display when you’re on battery power if you have the “Slightly dim the display while on battery power” option enabled.
Using the automatic brightness features won’t stop you from being able to adjust the brightness manually. If you ever don’t like the current brightness level, you can change it with a few keypresses. However, your Mac may automatically increase or decrease the brightness level if the lightning near you changes, and you may have to tweak it again.
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This option doesn't show for the LG UltraFine:
The brightness is adjustable using an external keyboard however.
It just doesn't seem to be adjusting automatically.
I've found the full manual online (it only comes with a quick start guide in the box), and it confirms the dot on the top is an ambient light sensor.
It also says:
Which implies the ALS is driven by macOS somehow. Perhaps the functionality will be added in the next point release?
And I've checked and the monitor's firmware is up to date, so it isn't that.
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Just updated to 10.12.2 on my 2015 Macbook and the automatic option has not appeared with the update. Also checked and my monitor seems up to date as well.
I have the exact same problem, currently running the latest macOS 10.13.3 and the latest LG Screen Manager 2.9, no automatic bright adjustment either
Where have they indicated that?
Both the 4K and 5K displays have been out well over a year, and they've released bugger all updates to it!
(Although AFAIR, they did fix the USB-C ports speeds and the sound control.)
Pretty poor to have to wait a ridiculous time for this, when the hardware is there.
LG is infamous for never ever updating their products. Tricked again 
But I too have the hope to see this update in the future. This monitor absolutely burns my eyes on the high brightness settings. Adjusting brightness between day/night sunny/cloudy is a pain. One thing I'm wondering is if the ambient light sensor is even a real thing or an oversight in the documentation.
I used this link to let them know and so should you (the monitor product number is 22MD4KA-B also send them a link to this thread): https://www.lg.com/us/support/email-appointment
But I too have the hope to see this update in the future. This monitor absolutely burns my eyes on the high brightness settings. Adjusting brightness between day/night sunny/cloudy is a pain. One thing I'm wondering is if the ambient light sensor is even a real thing or an oversight in the documentation.
I used this link to let them know and so should you (the monitor product number is 22MD4KA-B also send them a link to this thread): https://www.lg.com/us/support/email-appointment
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At last, this feature which they planned two years ago, now is ready for use (Purchase of new Mac required.). Yessir, seven seasons after UltraFine Display were announced (at 2016 October), MacBook Pro (2018) can use the light sensor component for True Tone. (I presume also automatic brightness adjustment will be enabled.)
edit 2018-07-18 add:
This post is misleading misinformation, proven wrong.
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This is utterly false advertising to me! How on earth do they think it's acceptable to make said functionality available ONLY on the 2018 MBP?!
They advertised such an important feature that works on these 5K's on their initial release with the 2016 MBP's, only for it to NEVER be turned on, then this BS! Good am I livid.
I'm pretty sure the ambient light sensor still does not work. The True Tone on the UltraFine display is based on the readings of the MacBook Pro's colour sensor.
Sure the 2016/17 don't have TT, so obviously no one would expect that.
But really, why do I have to manually adjust each display's brightness manually on my 2016 model, instead of them all just following and mirroring the MBP's sensor...?? (via a simple on/off check box in Display prefs!) How hard can that be.
So there's *still* no hardware/software/driver support for the ambient light sensor in the UltraFines on macOS?
I know this screen is meant to be hooked up to a recent Apple machine, but I have it hooked up to a Linux box; an Ubuntu 16.04 desktop to be more precise. While I was trying to adapt this project and to compile it on Ubuntu (https://github.com/csujedihy/LG-Ultrafine-Brightness), the ambient light sensor of my LG UltraFine 4K display got activated. I don't know how, because I also compiled the code on a Windows 10 machine, and it worked to adjust the brightness, but it never activated the ambien light sensor, and in fact, the code does not even contain anything to activate the sensor. On top of that, I have since then unplugged the display and re-plugged it, and I was not able to reproduce the behavior.
What I wanted to say though, is that while the ambient light sensor "feature" was activated, I was able to experiment a bit with it, and it did not seem to work well. It was during the day, but there was not much sunlight coming into the room. It was even a bit dark, and the sensor would constantly change the brightness of the screen as if it would be hesitating between two values. If I would shine a flashlight on the sensor, then it would bring the screen to full brightness. And if I would put a finger on the sensor to block all light, it would completely dim the display, and it would go completely black. So I would never want to use the ambient light sensor event if I were able to re-activate it. It does not work well at all. My guess, is that the light sensor never worked properly on those displays, and this is why Apple is not showing the Automatically Adjust Brightness option for these screens.
What I wanted to say though, is that while the ambient light sensor "feature" was activated, I was able to experiment a bit with it, and it did not seem to work well. It was during the day, but there was not much sunlight coming into the room. It was even a bit dark, and the sensor would constantly change the brightness of the screen as if it would be hesitating between two values. If I would shine a flashlight on the sensor, then it would bring the screen to full brightness. And if I would put a finger on the sensor to block all light, it would completely dim the display, and it would go completely black. So I would never want to use the ambient light sensor event if I were able to re-activate it. It does not work well at all. My guess, is that the light sensor never worked properly on those displays, and this is why Apple is not showing the Automatically Adjust Brightness option for these screens.
So none of this code has anything to do with the sensor? https://github.com/csujedihy/LG-Ultrafine-Brightness/blob/master/LG-Ultrafine-Brightness/main.cpp
As far as I can see, no. And there is not mention of the sensor on the project description page. The code is to adjust the brightness of the screen manually.
Well 2 years after this thread was started, I bought this monitor for my MBP 2018. It's great apart from this auto brightness issue.
However, as I always seem to dim the screen 2 clicks at sunset, in wondering... Does anyone know of an app that will automatically do that to the external display every day at sunset? Seems it might solve a lot of our frustration.
F.lux app only seems to adjust temperature, not brightness, from what I can tell.
Thanks!
However, as I always seem to dim the screen 2 clicks at sunset, in wondering... Does anyone know of an app that will automatically do that to the external display every day at sunset? Seems it might solve a lot of our frustration.
F.lux app only seems to adjust temperature, not brightness, from what I can tell.
Thanks!
I built a utility to work around the faulty ambient light sensor. It piggybacks on your MacBook's ambient light sensor, polling every 5 minutes, and synchronizes the LG display (or any other display's) brightness to match.
See: https://github.com/willsthompson/BrightRight
Maybe I'm misunderstanding the problem - but my UltraFine 23.7" displays both adapt automatically to room brightness with sensors built into each monitor. Using macOS 10.14.6 on a 2017 15" MBP with Touch Bar (
MacBookPro14,3)
MacBookPro14,3)