Understanding local dimming zones

Things change I've changed · 12 Mar 2024 at 12:24

I'm researching older 38" gaming monitors, for example I'm temped by this,

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The screen only has 12 dimming zones, looking at videos of this online if example there is a bright object in the corner of the screen with a black background that whole area around the object lights up which looks very bad, what I don't get is what is this achieving?, the reason I say this is if I have that same scenario on my current old X34 with no local dimming zone I don't suffer this problem and the screen looks to my eyes 'fairy' black around the bright object with no light bleed? It makes no sense to me, can this feature be turned off, and if it can I assume it would then act similarly to my current screen?

willhub · 12 Mar 2024 at 12:41

Is your monitor a VA panel? They have better blacks, or could just be your monitor whatever is better at blacks, but it won't be dark on a black screen fully.

My dell has very small number of local dimming zones, but HDR is still better despite what people say because it give enhanced brightness and contrast but you do notice the blooming around certain things but it doesn't bother me.

Things change I've changed · 12 Mar 2024 at 13:02

It's an IPS panel, I'm just struggling to see the benefits, look at this image for example,

You see where the screen is lit up up the left where the mouse is, are you saying with local dimming disabled the whole screen would be that grey? I have never witnessed any monitor without local dimming zones to be that poor at blacks, or is this due to the HDR brightness?

willhub · 12 Mar 2024 at 13:25

LCD panels can't compete with OLED for deep blacks but try to get as near with local dimming. You won't get an LCD hitting actually black such as an OLED panel where the pixels are off.

The simple fact is the local dimming is designed to turn the screen off and only illuminate what is on the screen, for example a circle on a screen moving, and because the local dimming zones are not granular enough this is why you get "blooming"

jwilliamson47 · 12 Mar 2024 at 17:02

I've tried two AOC miniled monitors. Despite the IPS one having a lot more zones than the VA and being lmost twice the price, the VA looked miles better. The contrast looked amazing with local dimming on strong and slight blooming.

The IPS model had awful blooming displaying logos and the contrast seemed mediorce to my eyes even with the max local dimming setting. It's possible the IPS one i got was a dud but just sharing my experience.

Five.Stars · 12 Mar 2024 at 17:07

Things change I've changed said:
It's an IPS panel, I'm just struggling to see the benefits, look at this image for example,

You see where the screen is lit up up the left where the mouse is, are you saying with local dimming disabled the whole screen would be that grey? I have never witnessed any monitor without local dimming zones to be that poor at blacks, or is this due to the HDR brightness?

I think that photo is slightly exaggerated by the curvature of screen, but yeah any screen with dimming zones with cause halo'ing. This is obviously mitigated by having a larger amount of dimming zones. My 34" Ultrawide has 56 zones, but it isn't enough and having got myself an OLED tv last year has made me consider upgrading to a similar sized 21:9 OLED.