Samsung 50-inch QN90A: cannot turn off global dimming?

[QFAN]

If I put a pure black background and just a white mouse cursor in the center of the screen, the screen turns dark globally, so the cursor is nearly invisible.

 

Already turned "Local Dimming" to "Low" (there's no "Off" option and there's no "Global Dimming" configuration).

 

Contacted Samsung Canada support and they first try to convince me to return the TV to the store and then think there's an electrical glitch.

 

 

[GuiltySpark_]

Maybe contact this guy? Seems its not a problem with your display, just how the display is designed.

 

Downsides to using a TV as a monitor.

[SansVarnic]

-= Moved to Displays =-

[QFAN]

Sorry, SansVarnic. I posted this to wrong subforum and thank you for moving it to Displays section.

[QFAN]

So, I spent 70 minutes with Samsung Canada Support, and after me trying to refuse their demand that me returning this TV to the store, and taking/sending photos, system reset, power cycle, the customer service finally said ok there's no such option to turn off global dimming.

[circeseye]

1 hour ago, QFAN said:

So, I spent 70 minutes with Samsung Canada Support, and after me trying to refuse their demand that me returning this TV to the store, and taking/sending photos, system reset, power cycle, the customer service finally said ok there's no such option to turn off global dimming.

yea samsungs hasnt had the option to turn off global dimming since the first 8000 series. not sure why but it is what it is

[Stahlmann]

This TV cannot disable local dimming. And the reason why your cursor is so dark is because of the local dimming algorythm. It doesn't fully light up a dimming zone just because there is 1 tiny bright object. This is to counter blooming.

 

Your TV is pretty much doing exactly what's expected and what it's supposed to.

[QFAN]

2 hours ago, Stahlmann said:

This TV cannot disable local dimming. And the reason why your cursor is so dark is because of the local dimming algorythm. It doesn't fully light up a dimming zone just because there is 1 tiny bright object. This is to counter blooming.

 

Your TV is pretty much doing exactly what's expected and what it's supposed to.

The reason I think it's not "local" dimming is that, when I put a white line at top/left of the screen, then the cursor becomes brighter even though it is located at far bottom right.

[Stahlmann]

1 hour ago, QFAN said:

The reason I think it's not "local" dimming is that, when I put a white line at top/left of the screen, then the cursor becomes brighter even though it is located at far bottom right.

Then it could be some sort of energy saving feature. Turn all of these off if you haven't already.

 

EDIT: Did you remember to mark your input as PC in your TV? This is an important step with many TVs that are used as a monitor.

[QFAN]

7 hours ago, Stahlmann said:

Then it could be some sort of energy saving feature. Turn all of these off if you haven't already.

 

EDIT: Did you remember to mark your input as PC in your TV? This is an important step with many TVs that are used as a monitor.

Energy saving is off. This TV also can auto-detect connection type and it's correctly detected as "PC". Not sure if there's any additional option to set connection type to PC even though it's already "PC" on the sources list.

 

Looks like the most reliable way to make sure no content is missing on screen (because it may turn too dark to see) is to never run anything full screen. Always keep a bright Windows taskbar at the bottom then the overall brightness won't be auto tuned down.

[Stahlmann]

11 hours ago, QFAN said:

Looks like the most reliable way to make sure no content is missing on screen (because it may turn too dark to see) is to never run anything full screen. Always keep a bright Windows taskbar at the bottom then the overall brightness won't be auto tuned down.

I never heard of anyone who had the same issue you are having. And your "solution" is more like workaround, which you shouldn't have to do on such an expensive TV. I'd contact the seller and tell them about your problem. Maybe even go as far as replacing it and seeing if it was just this one unit that had this strange global dimming.

[QFAN]

Here's demonstration of the problem.

- I taped a piece of white paper on screen so that camera can focus.

- Top-left is a reflection of a desk lamp to illuminate the paper, still for camera focus.

- The TV is connected to a PC

- The current displayed content is Photoshop program, displaying a black image with 20 white dots on it, in full-screen hide-all-toolbar mode.

 

Picture 1: all 20 dots are not visible.

 

----

Picture 2: draw an additional short line (about 1-inch on TV), then other 20 dots become barely visible.

 

Picture 3: draw a lot of white to the top left, then the brightness of other dots become mostly normal.

[Guru3d]

On 9/1/2021 at 3:28 PM, QFAN said:

Here's demonstration of the problem.

- I taped a piece of white paper on screen so that camera can focus.

- Top-left is a reflection of a desk lamp to illuminate the paper, still for camera focus.

- The TV is connected to a PC

- The current displayed content is Photoshop program, displaying a black image with 20 white dots on it, in full-screen hide-all-toolbar mode.

 

Picture 1: all 20 dots are not visible.

 

----

Picture 2: draw an additional short line (about 1-inch on TV), then other 20 dots become barely visible.

 

Picture 3: draw a lot of white to the top left, then the brightness of other dots become mostly normal.

Hi there , did you solve the problem ? I am having the same problem with this exact  model