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What is Local Dimming?

Updated Sep 17, 2014 By Cedric Demers
Vizio M Series FALD Off
LED TV with local dimming turned off
Vizio M Series
Vizio M Series FALD On
LED TV with local dimming turned on
Vizio M Series

Local dimming refers to the technology that changes the uniformity of the backlight of an LED screen. The television changes the luminosity of some zones of the screen to better reflect the scene and to create deeper blacks. It improves the weak black level of an LED TV, compared to the perfect blacks of a plasma.

Unfortunately, local dimming on LED TVs is rarely effective. Most LED TVs are edge lit, so they cannot control precisely the backlight. It works better on a full array LED TV (like shown in the pictures above), but it creates a blooming effect.

Unlike local dimming, Samsung Micro Dimming does not even dim locally the LEDs of the backlight. Instead, it is a software only feature that processes the picture to accentuate the contrast in different zones of the picture. More info on this later in this article.

In the pictures, you can see that the blacks for an LED with local dimming are darker than a normal LED because the lights behind that section of the screen are dimmed. However, you can see a slight halo effect, because the television still needs to have some bright LEDs behind the center cross. A plasma TV has no problem displaying deep blacks directly next to the cross.

Is Local Dimming worth it?

In theory, local dimming is great. It increases the perceived contrast of the picture by illuminating more the correct part of the screen and by turning off completely a dark section. LCD screens leak a little bit of light through the pixels, even when displaying a black color. By reducing the lights behind a region of the screen where the picture is mostly black, it reduces the leakage and produces a darker picture. The following illustrations show a backlight for a normal LCD, an edge-lit LED and a full array LED.

LCD backlight
LCD backlight
LED full array with local dimming backlight
LED full array backlight with local dimming
LED edge-lit with local dimming backlight
LED edge-lit backlight with local dimming

You can see that the backlight tries to match the picture to display, but there is some diffusion caused by the dispersion of the lights of the LEDs.

In practice, very few TVs can control precisely the backlight, due to the lack of a really granular backlight. The precision is not perfect and the size of the controllable zones varies between models. The worst case would be if you are watching a scene in space with stars. Overall, the scene is dark but the small stars are bright. The LEDs behind the screen affect a rather large area so it cannot only light up the backlight for the pixels of the stars. Depending on the implementation, it could produce a worst picture than before and could create a halo effect around the stars.

Does local dimming also work for edge-lit LED?

The majority of televisions with local dimming are edge-lit LED TVs. The resolution of the backlight of an edge-lit is a lot worse than a full array (see pictures above). The lights are on the edge of the screen, making it harder to control exactly a section of the screen. Instead of dimming a specific part of the screen, it is roughly the whole screen that will dim. It cannot be precise and it does not want to dim the brighter part of the image, so it will only slightly dim the darker parts.

To learn about the different types of backlight in an LED TV including edge-lit, check out how they work.

Here is a real example on an edge lit TV:

Samsung H8000 Local Dimming Off
Edge lit LED TV with local dimming turned off
Samsung H8000
Samsung H8000 Local Dimming On
Edge lit LED TV with local dimming turned on
Samsung H8000

The difference is really subtile. Because it is edge lit, it cannot improve the blacks inside the actual picture. Instead, only the top and bottom black bars are dimmed. It does overlap on the picture though. The top and bottom edges of the picture are darken.

Therefore, local dimming on edge-lit LED TVs (the majority of them) is not worth it. Only full array LED TVs can be effective, and they are very rare.

Manufacturers' Naming for Local Dimming

Each manufacturer has a different implementation of local dimming and references it by a different name.

What is Micro Dimming and Micro Dimming Ultimate?

Micro Dimming is Samsung's marketing response to local dimming (which is why the name is similar). However, Samsung does not actually dim the LEDs of the backlight, so it is not really local dimming. Instead, it artificially tries to create a similar effect by changing the contrast of different zones of the picture. Micro Dimming Ultimate claims to have twice the number of zones (600) and changes the color and sharpness in addition to the contrast.

Of course, this is mainly just a marketing feature and is nowhere near real local dimming. Video purist especially do not like it, because it messes with the video settings of their televisions, changing the contrast from frame to frame.

Which is why in all our reviews of Samsung TVs, we always set the mode to Movie to disable this feature.

You will not really see a difference between the different versions of Micro Dimming. As usual in the television business, the difference between them are more in term of marketing rather than real technology improvements. Therefore, we do not recommend the Micro Dimming technology. However, Samsung do put better panels in their higher end models, so the picture could be better (but not due to this technology).

Samsung TVs equipped with Micro Dimming are also equipped with CE Dimming. CE Dimming does dim the LEDs of the panel, but not locally. It dims the whole panel on darker scene. Some people do not like it, because you can actually see the whole screen dims sometimes, like in the end credits of a movie. There is no option to turn CE Dimming off, even in the service menu.

You can turn CE Dimming off indirectly though, by using the Movie picture mode.

What is Smart Dimming?

Smart Dimming is Vizio's name for its local dimming technology. It is used on some of their edge-lit LED televisions to dim the darker portion of the picture (see above for more information on local dimming for edge-lit televisions). The number of controllable zones varies depending on the model, but because it is still an edge-lit LED TV, we do not recommend that feature.

What is Frame Dimming?

Frame Dimming is made by Sony and is the equivalent of an edge-lit local dimming, but with even less zones. Instead of changing the light for a specific region of the screen, it is the whole frame of the screen that changes intensity. You can see it as a very basic version of local dimming. It is better than no dimming at all for dark scene, but it is nowhere near real local dimming.

Can you turn local dimming off?

Yes, the local dimming feature of most televisions can be turned off in the settings menu. It is sometimes hidden inside the service maintenance screen.

For Samsung TVs however, Micro Dimming cannot be turned off even in the service menu. If you want to watch television without it, you will need to set your TV in the Movie Mode, where this feature is disabled by default (among other features also).

Does a plasma TV also have local dimming?

Plasma TVs do not need local dimming, because they have no backlight. Each pixel emits their own light and are independent of each other, so it can produce a white color right next to a black color with no leakage. Therefore, plasma do not have the problem that the local dimming technology is trying to solve for LCD/LED displays.

Learn about how plasma works here.

Conclusion

Unless it is a full array LED TV with a good implementation of local dimming, skip that feature. It does help with the blacks, but it can create a blooming/halo effect. Local dimming is even less useful for edge-lit LED TVs (most of them), because it cannot dim only a specific part of the screen.

Questions

Apr 08 2013
Is there a difference between the Samsung F6300 and F6400? I think the 6400 has micro dimming (and 3d but thats another thread), will micro dimming make it noticeable on these 2013 models?
The two main differences are 3D and Micro Dimming. If you do not care about 3D, you are probably better buying the F6300. Unless the price difference is really small, micro dimming alone is not worth it.
21
Sep 11 2012
How do I turn off Micro Dimming on my Samsung UN55ES8000?
Sadly, you can't. Even in the service menu, there is no option to turn off Micro Dimming on the Samsung models for 2012. You can however set the TV in Movie mode, which has that feature turned off (but also with other settings).
13
Feb 01 2013
Is the LG LM6200 a full array with local dimming or edge? What's the difference between this model and the LM6400?
Both the LG LM6200 and LM6400 are edge-lit LEDs, but only the LM6400 has local dimming. Also, the LM6400 has a slightly different bezel.
7
Mar 04 2013
I recently picked up a Sony XBR8 55". It seems to have a problem with the local dimming and frame doubling board. It'll cost about $200 to replace it. How does that television compare to current model televisions with local dimming?
The Sony 55XBR8 is a really good TV, even for a 5 year old TV. Not only it is a real full array local dimming, but the LEDs behind it are not white; they are separate colors in packs (2 green, 1 red and 1 blue). It still has a slight halo effect like most full array though. While the top TVs of 2012 are better, the 55XBR8 is in the same ballpark. Therefore, it is worth repairing it for 200$ instead of buying a new TV.
6
Nov 13 2013
Looking at buying Samsung F7100 or the ES7100 55 inch. Is there a big difference?
They are similar. The only noticeable difference picture quality wise is the better backlight uniformity. Besides that, it is only cosmetic changes, newer software and smart features.
6
Apr 01 2014
I want to buy a Samsung LCD 46" but I can't decide what is best in terms of image quality, in first place I thought in F6800, but then I regret because it has Micro Dimming, and not Micro Dimming Pro or Ultimate, what would you recommend? Go for that one anyway? Save some money for F7500 (worth it?) Or some lower series? The only aspect I care is image quality.
If you only care about picture quality and do not like an over processed image, get a lower Samsung instead like the F6300. Micro Dimming is a software only processing and most people (including us) prefer it disabled by setting the mode to Movie. Some people do like an over processed picture though.
5
Nov 20 2012
Does the LG 42ls3450 have local dimming or global dimming?
The LG 41LS3450 does not have local dimming. It is an edge-lit LED TV. It can control the overall brightness of the backlight though via the features called "Smart Energy Saving" and "Intelligent Sensor". The intelligent sensor is an ambient light sensor placed in front of the TV. If it detects a dark room, it will lower the backlight intensity. You can also manually control the intensity of the backlight in the menu by changing the "Smart Energy Saving" settings.
3
Dec 11 2012
Is it better to buy a Samsung plasma 42" or the Samsung LED EH5300 40", as you said that there is no models in Samsung coming with full array with local dimming?
A Plasma TV and an LED TV are two completely different beasts, check out our guide here. If you are worried about blacks (hence looking for a full array local dimming model), you better go with a Plasma then. They are not for everyone and they comes with their own set of drawbacks, so make sure to check out the guide.
3
Jul 28 2013
Is the Samsung F7500 a full array or edge lit TV?
Edge lit
3
Sep 01 2013
I want to buy a Samsung LED HD TV with 3D but I am not able to choose the model. Please suggest which model is good in terms of good picture quality and price.
The best price/quality ratio for a 3D Samsung LED TV is definitely the Samsung FH6030. It is a barebone TV with no Smart features, but its picture quality is great for the price.
3
Nov 04 2012
I am on the edge of buying a led/plasma tv (42") but can't decide on it. I am told that led only makes sense when it is full array local dimming. But again it is very expensive. I like plasma display, but am hesitating for its heating & power consumption. Advices for led(which technology) or plasma, with brand and model names is appreciated. Thanks. Vinod
Local dimming is only good for full arrays, but an LED backlight is still worth it for its thinnest and lower power consumption compared to a traditional LCD backlight. Plasma do offer better picture in dark rooms though. If you check out our LCD vs LED vs Plasma guide, you will see that it cost only about 20$ more per year for a 42" plasma for electricity. There are very few good plasma model at 42", the best one probably being the Panasonic 42UT50.
2
Nov 26 2012
Does the UE40ES6530 from Samsung has micro dimming? Is it full array or edge LED? Is it a good TV?
Unlike its US equivalent, the ES6500, the Samsung UE40ES6530 does have micro dimming. It is an edge lit screen, where the LEDs are at the bottom like most of the Samsung LEDs.
2
May 06 2013
My question is what are typical difference on US and Europe's TV's? Is it about Hz only?
It depends on the model and country. Generally, it is only law compliance differences but sometimes some software features are different. Some country also get more sizes than others, mostly to accommodate the supplies.
2
May 09 2014
I am trying to decide on a Samsung LED TV, the HU8550 or the H8000 LED. Which one is the best all around 55"?
We haven't test the HU8550 yet but we did test the H8000. Besides the 4k resolution, we don't expect a difference in the picture quality. So if you sit at more than 7 feet, go for the H8000 because you won't notice the 4k resolution anyway at that distance.
2
Nov 20 2012
What is the best 40"-46" led tv with 3-4 hdmi inputs? I was going toward Samsung UN40ES6100; but really don't want or need Smart Tv; since I don't have internet.
The UN40ES6100 is a good choice for the price. However, if you do not need Smart TV features, go for the UN46EH6000. For about 50$ less, you get a 6" bigger screen. It only has 2 HDMI inputs, but you can buy a HDMI switch for about 20$ to connect more.
1
Nov 28 2012
Is it better to buy a full array LED TV vs an edge LED TV? Can you give me an example of a full array for a Samsung 40"?
Yes, a full array LED TV is better for local dimming. Beside the higher cost, the downside is a thicker panel though. There is no current Samsung 40" that has a full array backlight.
1
Dec 15 2012
How do i turn off local dimming in my LG LW5600?
In the Picture settings menu, set the option called "LED Local Dimming" to Off.
1
Dec 18 2012
How about the LG 72LM9500, is it full array LED with local dimming?
Yes, the LG 72LM9500 is a full array LED TV with local dimming. The LM9500 is the equivalent of US LM9600.
1
Jan 08 2013
Can I turn local dimming off on 47LM7610?
Yes, look for the setting called "LED Local Dimming" under "Picture Quality".
1
Feb 28 2013
Does the LG 32" 6410 has local dimming?
Yes (edge lit local dimming).
1
Jul 01 2013
What are the 32" full arrays local dimming led TV models for LG and Samsung?
They don't exist. Full arrays are only available on big size TVs. A lot of them are direct lit though.
1
Aug 19 2013
Can you turn off local dimming on LG 55ln5710 or 60ln5710?
There is no local dimming on these TVs. It is the whole screen that dims and yes it can be turned off (look for the eco setting).
1
Oct 26 2013
Could you advise if Toshiba 47RW1 is full array local dimming?
No it isn't.
1
Aug 04 2014
Any suggestions on whether to buy the new Vizio m492i-b2 in terms of picture quality with the implementation of the new full array local dimming? According to cnet, the new Vizio tv has amazing picture quality. I'm on the fence with the vizio or the sony KDL48W600b.
We will start testing Vizio TVs soon. We don't have high hopes for the full array local dimming on them. We expect our actual contrast ratio measurement to stay unchanged even with that option turned on because we use a checkboard pattern. Keep in mind that CNET uses a 95% black pattern for its black level test, which favors local dimming (even edge).
Update: The review of the M552i-b2 is up now.
1
Jul 13 2012
I hesitate between two HDTVs, one with local dimming, and the other not. Should I buy the more expensive one?
If all other things are equal, no, it is not worth it. Most likely, you will not see the difference especially if it is an edge-lit LED screen.
0
Aug 21 2012
Does the UE40ES6100 use local dimming? Is the UE40ES6710 better?
No, it doesn't. The ES6710 however do have Micro Dimming. As explained above, this is not actually local dimming, because the backlight does not dim. You wouldn't really see a difference between the two if they are both calibrated correctly.
0
Oct 02 2012
Does the Sony EX650 LED TV have local dimming?
No, the Sony EX650 does not have local dimming, not even frame dimming. However, its US equivalent, the EX640, is equipped with frame dimming.
0
Jan 11 2013
Of the two, which would you recommend: LED Full array without local dimming or LED Edge lit with local dimming?
Assuming a real one, an LED full array without local dimming. A say a real one because most direct-lit LED have very few LEDs behind that you can actually see them. A real full array LED will have a lot better backlight uniformity than an edge-lit. In an edge-lit, not only the local dimming is not really efficient, but they have a lot of issues with backlight uniformity like flashlighting or clouding. Of course though, in the end it really depends on which model.
0
Feb 19 2013
Is the Samsung UN55EH6050FXZA Full Array Backlit or Edge Lit. There website doesn't indicate. What is the difference between the "6050" vs. the "6000" besides who sells them? Both appear to be "price point" LCD/LED TV's.
The Samsung EH6050 is direct-lit, not edge-lit. It isn't a full array though, because the number of LEDs behind the screen is very limited. The EH6050 is exactly like the EH6000, but it is a version unique for wholesale stores.
0
Feb 21 2013
Is it worth it buying Samsung ES9000 with local dimming over Samsung ES8000?
There is no doubt that the ES9000 has a better picture quality than the ES8000. It also comes in the 75" size while the ES8000 is limited to 65". The more important question is if the difference in price is worth the increase in picture quality? Only you can answer this depending on how you value your money and picture quality. Note that the ES8000 is an overall very good TV, so it might well be enough for you. That being said, the price jump is really high and if you are willing to spend that amount of money, you should probably wait for the 2013 models to come out later this year.
0
Feb 28 2013
I have a LG 55" LM6400. It seems to have what they call clouding or led bleed through on the top left edge of the screen. Is there any way to correct that or is the tv defective?
Check out our article on this issue here. Most of the time, it cannot be fixed. Your only option, if it does bother you a lot, is return it and get another unit of the same model. This kind of issue is common on low to mid level LED TVs.
0
Apr 23 2013
Is the Samsung UN50F6300 edge lit or full array?
Edge lit.
0
Jul 06 2013
Why don't manufacturers use full array local dimming in all their large flat panel LCD/LED sets?
It greatly increase the cost of the display as well as making the TV thicker. Also, it doesn't improve the quality of the picture by a huge amount.
0
Jan 23 2014
Given two models like the Samsung UN32EH5300 direct lit and a Samsung UN32F5500 edge lit, which would have a better picture? The 5300 has a deeper case but aside from dual smart processors what differences might be expected between these two technologies?
They are very similar. The only noticeable difference is like you mention the backlight. Direct lit LEDs tend to have a better uniformity than edge lit. Besides this, you will not really see a difference in the picture quality.
0
Jan 25 2014
I'm after the Samsung UN75F7100 75-Inch 1080p 240Hz 3D Smart LED TV, was going to buy it in Dec2013 but had other expenses, I do now want to buy it now, but I noticed that in December it was $500 off and then it went back to $4,999.98 and as of this present week 1/25/14 it went back down $500 to $4,499.98 (I assume SuperBowl). My question is, will it go cheaper than that, as in $1,000+ down? And what time of the year is it best to buy big smart TVs with $1,000+ off?
If you haven't already, check out the price history chart of that TV here. Usually, November is the best time of the year to buy TVs (around Black Friday). Price after that are either around the same or slightly higher than November until there is no stock left. In March-April, if the demand for a TV is lower than anticipated (aka: they are still some stocks left at that time), you can get an even better deal especially if you negotiate it in a retail store. New models are out around that time so retail stores want to get rid of their old stocks.
0
Jun 12 2014
What is micro pixel control in LG TVs? Does it give significantly better picture?
It is LG's name for local dimming. Its effectiveness depends on the model, but most models aren't very precise.
0
Jun 23 2014
Is the LG 55LA9700 a LED full array backlight with local dimming, if so where is the local dimming settings, which local dimming setting switched on/off improve quality of the picture, also which settings stops halo around white images on black backgrounds.
Full array. We haven't test it though so we don't know what the setting is called for local dimming in the menus.
0
Aug 21 2014
Samsung UN50H6400 or UN50H6350 or UN55H6203 or UN50F6300? Which one is better if we combine image quality and smart functions?
The UN50H6400, especially if you care about smart features. The remote alone makes it worth it.
0
Aug 25 2014
Lg 70lb7100: LED backlighting - says along with micro pixel control, tru black control, a resolution upscaler and triple XD engine delivers amazing brightness, clarity and color detail. What does all this mean and is this tv full array or edge lit?
This is all marketing talk. It just means it is an edge-lit TV with local dimming.
0
Sep 04 2014
Eco sensor on or off for the Sony kdl42w700b?
The ECO sensor is just an ambient light sensor that adjust the luminosity of the screen depending on your room. It doesn't affect the picture quality. Some people prefer turning it off to have full control over the backlight, others leave it on to prevent changing settings between daytime and nighttime viewing.
0
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