Brightness Jumps - Is it Normal?

[Sovon Halder]

I got this 4K 27" LG Monitor (27uk850) hooked up with macbook pro 2017 13" via USB-C.

This happens on the external monitor.. When I'm playing a video or streaming a video, throughout the playback the brightness jumps up and down by very minimum amount (say 1%). It happens randomly & couldn't find any specific pattern when it happens & I more noticeable while streaming youtube/netflix. However I can replicate one thing; when I pause a local video, within 2-5 seconds, the brightness jumps up by that tiny amount. And this happens every time(almost).

I recorded my screen to capture this alien phenomenon. If I play that on the 27" monitor, that flicker is there but on the macbook screen it doesn't show. Also I noticed that if the window size of the media player is made smaller, that brightness shift isn't noticeable.

Here are two recordings. (Excuse the file size)

https://www.dropbox.com/s/9ix3b31a772y2c3/Brightness-shift.mov?dl=0
https://www.dropbox.com/s/nc215yd2302jgqg/shift-2.mov?dl=0

Is this normal? If anyone can shed some light on this, please help. I got no clue.

 

[uller6]

I got this 4K 27" LG Monitor (27uk850) hooked up with macbook pro 2017 13" via USB-C.

This happens on the external monitor.. When I'm playing a video or streaming a video, throughout the playback the brightness jumps up and down by very minimum amount (say 1%). It happens randomly & couldn't find any specific pattern when it happens & I more noticeable while streaming youtube/netflix. However I can replicate one thing; when I pause a local video, within 2-5 seconds, the brightness jumps up by that tiny amount. And this happens every time(almost).

I recorded my screen to capture this alien phenomenon. If I play that on the 27" monitor, that flicker is there but on the macbook screen it doesn't show. Also I noticed that if the window size of the media player is made smaller, that brightness shift isn't noticeable.

Here are two recordings. (Excuse the file size)

https://www.dropbox.com/s/9ix3b31a772y2c3/Brightness-shift.mov?dl=0
https://www.dropbox.com/s/nc215yd2302jgqg/shift-2.mov?dl=0

Is this normal? If anyone can shed some light on this, please help. I got no clue.

I had a similar problem with my MBP on an external Samsung monitor recently. It took me forever to find the issue - I finally discovered the problem was with the "auto brightness" settings on the monitor continuously trying to adjust the monitor brightness. Once I disabled this setting the flickering stopped. Hope that solves your problem...

 

[Sovon Halder]

I had a similar problem with my MBP on an external Samsung monitor recently. It took me forever to find the issue - I finally discovered the problem was with the "auto brightness" settings on the monitor continuously trying to adjust the monitor brightness. Once I disabled this setting the flickering stopped. Hope that solves your problem...

I should have updated my post earlier. Someone on reddit told me precisely what was causing it within 10 minutes of posting there. Turns out it is "Smart Power Saving", an LG initiative of going green (it adjusts overall luminance 'intelligently').

I was sensitive to it and found it very annoying since day one. I used the monitor like that for about 15 days and I was thinking I was going to have to just live with it. It got on my nerves and then I posted seeking a solution on social media. Anywho.. it was just a toggle. I turned it off and voila. Fell in love with my 27" 4K HDR monitor all over again.

This should definitely NOT be turned on by default, IMO.