How many local dimming zones are good for a TV?

OLED TVs are the kings of contrast, with those deep, inky blacks and super-fast response times, all thanks to their self-emissive pixels.

Regular LED LCD TVs just can’t match that, since they rely on a backlight instead of pixels that light up on their own like OLEDs.

But is there a way for LCDs to get close to OLEDs in terms of contrast and black levels?

That’s where local dimming steps in.

In LCD TVs, the LED backlight is split into multiple dimming zones.

Now, the question is:

How do these dimming zones actually work, and what is the sweet spot for the number of zones needed for an LCD to get near OLED-like performance?

What is a dimming zone in an LCD TV?

LCD TVs use the method of local dimming boost their contrast ratio.

Basically, the LEDs in the TV’s backlight are split up into groups, commonly called lighting or dimming zones.

Each zone corresponds to a specific part of the screen, and can turn on or off independently depending on whether that part of the image is bright or dark.

By controlling these zones separately, LCD TVs can achieve deeper blacks and a better contrast ratio.

Now, it’s pretty clear that having independent dimming zones in an LCD TV can really help boost its contrast ratio.

But you would have probably seen TV ads bragging about the number of dimming zones—maybe 200, or even 20,000.

So, what number of dimming zones is actually “the best” for a TV?

Is there a link between the number of dimming zones and the contrast ratio?

And if there is, is there some magic formula that explains how they’re connected?

That’s exactly what we’re going to dig into next in this article.

Number of dimming zones vs contrast ratio

LCD TVs use either IPS or VA panels, though VA panels are more common since they offer a better native contrast ratio.

And a better contrast ratio leads to deeper blacks, better HDR performance, and overall nicer picture quality.

To push contrast even further, LCD TVs use dimming zones, which make the image look more realistic.

They also help cut down on haloing, that glow you sometimes see around bright objects against a dark background.

So, the question is: how many dimming zones does a TV actually need to eliminate haloing?

An article published by Optica Publishing Group found that to make the halo effect basically invisible, an LCD TV with a contrast ratio of around 5000:1 needs roughly 200 local dimming zones.

But if the contrast ratio is only about 2000:1, you’d need more than 3000 zones to pull it off.

So, it’s pretty clear—The higher a TV’s native contrast ratio, the fewer dimming zones you need to hide halos.

Now the big question: what’s the “magic” contrast ratio for OLED-like performance?

OLEDs technically have an infinite contrast ratio, but what’s the closest real-world number—1,000:1, 10,000:1, 100,000:1, or as large as a million-to-one?

That same study says an HDR display needs a contrast ratio of over 100,000:1 to show fine details in both bright and dark areas simultaneously.

Okay, we got some numbers.

Let’s proceed ahead.

How many local dimming zones are good for a TV?

So, how many dimming zones would an LCD TV need to match an OLED’s picture quality?

The short answer—millions.

That’s because an OLED TV has millions of self-emissive pixels, and each one can switch off completely in dark scenes, producing zero light.

This is what gives OLEDs those deep, inky blacks and their “infinite” contrast ratio.

For an LCD to pull off the same, it would need just as many dimming zones as an OLED has pixels—which means building millions of LEDs into its backlight.

But that would be insanely complex and ridiculously expensive.

That said, there is a completely different technology called micro-LED, which uses inorganic LEDs as individual pixels, but that’s another story.

Here, we’re sticking to backlit LCDs.

How do 50, 100, 500, 1000 zones compare to OLED/QD-OLED?

Imagine there are 50,000 students in a competition.

A student ranked 5,000 would be at the 90th percentile, while someone ranked 1,000 would be at the 95th percentile.

Now take three others, A, B, and C, ranked 1, 100, and 250 respectively.

Their percentiles would be 99.998, 99.8, and 99.5 respectively.

But here’s the thing, once you’re above 99.5 percentile (or even 99), does that tiny difference really matter?

You see what I’m getting at?

Let’s put OLED right at the top spot—rank one.

Now, imagine an LCD TV with 5,000 dimming zones sitting at rank 100, and another LCD with 1,000 dimming zones at rank 250.

When you compare their black levels and contrast, there’s no doubt OLED still wins hands down.

But those mini-LED TVs with 1,000 and 5,000 zones aren’t that far behind.

They can also deliver impressively deep blacks, though they are not exactly like the blacks on the OLEDs.

But here’s the question: does it really matter if our eyes can’t tell much of a difference?

The human eye has a finite resolution, so beyond a certain point, the improvements get harder to notice.

If a TV with 1,000 zones is already giving you deep blacks and an excellent HDR experience, what’s the point of adding 5,000 or 10,000 more zones for just a tiny visual gain?

After all, matching OLED black levels would ideally require millions of dimming zones, which just isn’t practical.

And as for where the line of diminishing returns lies—well, that’s still anyone’s guess.

Moreover, the contrast of an LCD TV isn’t just about how many dimming zones it has.

It’s equally influenced by the panel’s native contrast ratio before local dimming is even applied, as well as the method of local dimming itself.

In fact, it may be possible for a brand-new TV with only 200 dimming zones to match the contrast of an older TV with 2,000 zones, simply because the local dimming methods and algorithms have been continuously improving over time.

So, just knowing the number of dimming zones, whether it’s 50, 100, 500, or even 1,000—doesn’t really tell you how close an LCD TV is to an OLED or QD-OLED when it comes to contrast and picture quality.

Conclusion

There’s no magic number of local dimming zones that guarantees the best results.

That said, if you’re in the market for an LCD TV, look for one with a VA panel and mini-LED backlighting.

VA panels inherently have good contrast, and when paired with mini-LED backlights, they take it to the next level as a mini-LED backlight typically has thousands of tiny LEDs creating several dimming zones.

In a dark room, these LCD TVs can give you an experience surprisingly close to OLED.

Plus, they can also get extremely bright in a bright room too, making HDR details truly pop.

However, when it comes to viewing angles and response time, OLEDs are still in a league of their own.