It is confusing. There are two separate "features."
CE Dimming: You cannot disable this feature in any setting. This is when the set automatically turns down the brightness during dark scenes to minimize flashlighting and clouding that some sets have. You can bypass it as above
Microdimming plus: This is a misnomer that actually has nothing to do with dimming the set. It does some "active scanning" voodoo to tweak the contrast but does not do any actual hardware dimming. Most of us think it is fake and not a real impact on picture. It is on by default in all modes but movie mode, which it is inactive.
See this post: http://www.avsforum.com/t/1399319/official-samsung-unxxes8000-owners-thread/7620#post_22681768
"By maximizing the contrast between lights and darks, Samsung's Micro Dimming technology displays a picture that is as true-to-life as possible. Our innovative technology scans zones across the image and adjusts brightness to deliver deeper dark tones and brighter whites. It also eliminates the "halo" effect and image distortion that can happen with diffused lights. The Ultimate version of this technology optimizes the quality to new heights by scanning 2x the number of zones in the image. The result is a crystal-clear picture with realistic, vivid detail and accurate color reproduction."
"Ever watch a movie and find it’s hard to see an object in the background? Micro Dimming Ultimate analyzes each frame of video in hundreds of areas to optimize the LED backlight and video signal for each frame in real time. By increasing brightness in the areas of the frame that are too dark to see, an overall 20% increase in brightness is achieved and finally you can make out that zombie lurking in the dark! Along with an overall brighter picture, Micro Dimming Ultimate will also produce more vibrant and richer colors."
Supposedly Micro Dimming Ultimate in the 8000s has 600 zones, which is double the zones that Micro Dimming Pro has in the 7500s. This feature is on by default in all modes except Movie mode. You can't turn it on in Movie mode.
There is very little information on this technology, but here's what it does. During a dark scene, the panel will automatically dim itself to give you deeper blacks and less apparent clouding. The reason we refer to it as CE Dimming is because it is in the service menu named that way. There were past TVs that you could turn it on or off from the service menu, but you can't on the ES TVs. It is on by default on all modes except Movie mode and the profession calibrator's modes, Cal-Day and Cal-Night. Some people don't mind or notice it, while it drives other people crazy. It appears that it may be more obvious on the ES7500 series than on the ES8000 series though this isn't confirmed. Because of this, some of us think that it is somehow tied to the Micro Dimming zones. You will most likely notice it during credits in a movie, or perhaps a movie with a lot of star fields. It is also very evident in the very dark movies of the Harry Potter series, but hard to tell because the whole movie is darker. What you'll realize is that you have to bump your backlight up more to see the film correctly. Why? Because the whole film has been dimmed. The reason it drives some crazy is because of the following. Say you watch a lot of science fiction. The scene cuts to a star field and you see the stars dim over a couple of seconds. Then a ship or planet comes into view and you then see the screen brighten. It can be distracting. There is a way to diminish or possibly even disable this "feature" though. It reacts to a threshold set by the Brightness setting. The higher you have Brightness, the less CE Dimming comes into effect. The problem is that your panel is now hazy and not calibrated with a higher Brightness setting. This can then be offset by turning down each of the White Balance Offsets, R, G & B accordingly. If you turn Brightness up by 7 points, turn down each White Balance Offset by 7 points.