Samsung UA40D6600WR LED disable auto dimming - Page 2 - AVS Forum
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post #31 of 37 Old 08-10-2012, 11:54 AM
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Originally Posted by PlasmaPZ80U View Post

The poster was referring to an auto-dimming backlight 'feature' that dims the whole backlight at once based on the APL of the scene at any given moment. Since this is global dimming, not local dimming, it doesn't improve ANSI contrast ratio and just dims all shadow detail and everything else in darker scenes. So, the 'feature' is not desirable to many and that's why those people want to disable this thing completely (although on some Samsungs, it is still active in movie mode and can only be minimized by cranking the shadow detail control all the way up... this varies from model to model, though... so the shadow detail control may affect low-end gamma on some sets and auto-dimming intensity on others).
I had this issue on a Samsung LND550 LCD last year and movie mode did not disable the auto-dimming. Setting shadow detail to +2 helped a lot though, by stopping the auto-dimming on everything short of a blank/completely black screen. However, this issue bothered me enough that I eventually returned the set (though other issues also affected that decision).

Dimming of the backlight STILL does not remove shadow detail... ever. If shadow detail is gone, it is not because of dimming. When dimming is employed, the LCD panel makes the same images whether dimming is on or off (if the panel is designed properly). The LCD panel is analogous to a 35mm slide (film) and the backlight is analogous to the projection lamp... you can make the projection lamp as bright or as dark as you like, but the 35mm slide will always contain the same amount of shadow detail. So will the LCD panel unless the Dimming feature does more than just control the backlight. The Dimming feature would also have to manipulate the black level (make it lower so dark steps are lost) for shadow detail to be lost when it is enabled.

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post #32 of 37 Old 08-10-2012, 04:42 PM
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Originally Posted by Doug Blackburn View Post

Dimming of the backlight STILL does not remove shadow detail... ever. If shadow detail is gone, it is not because of dimming. When dimming is employed, the LCD panel makes the same images whether dimming is on or off (if the panel is designed properly). The LCD panel is analogous to a 35mm slide (film) and the backlight is analogous to the projection lamp... you can make the projection lamp as bright or as dark as you like, but the 35mm slide will always contain the same amount of shadow detail. So will the LCD panel unless the Dimming feature does more than just control the backlight. The Dimming feature would also have to manipulate the black level (make it lower so dark steps are lost) for shadow detail to be lost when it is enabled.

Your missing the point... I didn't say that auto-dimming removes shadow detail but rather it's an undesirable 'feature' that dims everything in dark scenes, making no improvement to ANSI contrast ratio (unlike local dimming). Also, dimming the shadow detail does make it harder to see (especially if the dimming is very aggressive, which is yet another reason to avoid auto-dimming). That's all.
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post #33 of 37 Old 08-11-2012, 01:26 PM
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Auto-dimming (full screen) is JUST as useful and desirable as an auto-iris function in a projector... IF the feature is implemented properly. The point isn't to somehow magically increase contrast ratio. The point is to make the panel overall darker in dark scenes so the residual light level for black is not so obvious/distracting.

Of course you can do an auto-iris feature very poorly and you can certainly do full-screen dimming poorly. If either one is done CORRECTLY they are HIGHLY useful and DESIRABLE. Local dimming is potentially better but it does have blooming issues that can be distracting in their own right.... and obviously, you can't locally-dim an edge-lit LCD panel... the TV would have to have an LED matrix behind the screen (not just at an edge). Somehow, Sony seems to have the auto-iris feature totally under control. All any projector or LCD manufacturer would have to do is duplicate Sony's speed and amount of dimming for various picture levels and they'd have a full-panel dimming feature that would be just about impossible to criticize.

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post #34 of 37 Old 08-11-2012, 01:45 PM
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Quote:
Originally Posted by Doug Blackburn View Post

Auto-dimming (full screen) is JUST as useful and desirable as an auto-iris function in a projector... IF the feature is implemented properly. The point isn't to somehow magically increase contrast ratio. The point is to make the panel overall darker in dark scenes so the residual light level for black is not so obvious/distracting.
Of course you can do an auto-iris feature very poorly and you can certainly do full-screen dimming poorly. If either one is done CORRECTLY they are HIGHLY useful and DESIRABLE. Local dimming is potentially better but it does have blooming issues that can be distracting in their own right.... and obviously, you can't locally-dim an edge-lit LCD panel... the TV would have to have an LED matrix behind the screen (not just at an edge). Somehow, Sony seems to have the auto-iris feature totally under control. All any projector or LCD manufacturer would have to do is duplicate Sony's speed and amount of dimming for various picture levels and they'd have a full-panel dimming feature that would be just about impossible to criticize.

This thread is about Samsung LED/LCD flat-panels, not projectors and if this feature was desirable to the OP and other posters in this thread, the title would not read "LED DISABLE AUTO-DIMMING."

Also, there is a sort of local dimming on some edge-lit LED-LCDs, though it has fewer zones and is generally less effective than true local dimming on full array sets. Nobody is talking about projectors or Sony in this thread but you, only about Samsung flat-panels (mostly LEDs/LCDs and one poster is talking about a plasma). So, this side discussion really does nothing to help the others in this thread who want to disable auto-dimming on their Samsung flat-panel TVs.
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post #35 of 37 Old 08-16-2012, 03:30 PM
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Originally Posted by PlasmaPZ80U View Post


trying maxing out shadow detail in the user picture menu, advanced section
this might minimize the dimming with everything but a completely black or blank screen

You're a genius. I've been pulling my hair out over this auto dimming crap on my UN55C6300 for a year now, and bringing my Shadow Detail up from -2 to -1 did the trick.

Thank You!!
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post #36 of 37 Old 08-16-2012, 03:40 PM
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You're a genius. I've been pulling my hair out over this auto dimming crap on my UN55C6300 for a year now, and bringing my Shadow Detail up from -2 to -1 did the trick.
Thank You!!

glad to help; on the LND550 I had, I needed to go to +2 (but I suppose the 'C' LED models could be different)
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post #37 of 37 Old 08-16-2012, 04:00 PM
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According to Samsung on different model, "0" disables auto dimming. I have had mine set to "0" from day one, and haven't had an issue.


http://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?idx=161759&modelname=UN46C9000ZF&modelcode=&session_id=NJ2H4hpMLRzlGdj4RzLXr0K8VYwppbvcSQyjslnTxmD1RWX8QFQq%21640189940%211761676348%217501%21-1%21-944161233%211761676444%217501%21-1%211296659975846

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