Auto brightness limiters (abl) in plasma sets - Page 2

I don't get cable or anything like that. Just Netflix and Amazon Video all off of my PS3. I haven't been able to see any difference with the menu and my screen. I keep my contrast at 94 for the time being. Not sure if that or just the source could be why you are seeing problems and I am not? I am also using HDMI 1. Sorry I cannot be more help.

I have a GT50 and I have the exact same problem, so though I'm hoping my set is defective (since I like it otherwise), I think this is just plain old ABL in action. I've tried basically EVERYTHING to prevent it from happening, but to no avail. Granted, you can bump down your contrast and brightness to (50-60) so the auto brightness limitation isn't noticeable, but I don't like to watch TV or movies that way. Maybe some do, it would seem.

Granted, perhaps it's not a dealbreaker unless you watch a lot of hockey, play hockey video games or ones with snow, or connect your PC on your plasma for things like web browsing...unfortunately, 3 things I do. I believe this is why you don't hear more people complaining about it, since obvious ABL is only common for most in an instant in things like commercials (i.e. who cares).

See, I don't have a problem with whites being dimmed and the rest of the images on the screen being affected...but that's not the case. The WHOLE screen goes into low contrast mode and it becomes a grayish mess. There's an all around sharp drop in contrast while the screen is dimmed.

Anyway, it sucks. Like I said I like the TV, but I'm probably gonna end up returning it for an LED-LCD that I'll pay more for, and that doesn't match up to the GT50 in many categories...but I'll take that over what I personally find to be a glaring limitation of the technology. Wish I didn't see it that way though...

Let me chime in again, even though I don't own a U50. What you have just described does not sound abnormal to me. A mostly white screen, as seen in many commercials, should have roughly the same affect as an entirely white screen -- which should dramatically lower the luminance of any plasma TV. I have owned only one plasma, so I'm not the most knowledgeable person on this subject, and I'm not claiming to be. But just based on my limited experience with my own TV and from reading about (and seeing) other plasmas, what you describe here sounds normal to me. I do own a colorimeter, so I can give you actual measurements from my own TV, which may give you an idea of how ABL affects brightness in different situations. These are measurements from my own plasma (FWIW, a lowly 2010 720p Zenith [LG] with a black level of ~0.012 fL, decent color accuracy, and some deficiencies that aren't relevant to this conversation):

White window pattern: ~35.4 fL
4x4 ANSI pattern: ~29 - 32 fL
Full white: ~16 fL

Needless to say, there is a pretty dramatic difference between a white window and a completely white screen. FWIW, this plasma is capable of a much higher peak luminance than 35 fL, but the effect of ABL would not be diminished by increasing the peak brightness. And while my TV is admittedly not the pinnacle of plasma technology (far from it, obviously), I don't think that newer, better plasmas are really any better in regard to the severity of ABL. In his review of an ST50, Chad B said that he measured white on that display at only 22.18 fL using a 3x3 ANSI pattern. That's pretty low. I mean, it's not bad or surprising for a plasma (and it does result in extremely high contrast with the low MLL of the ST50), but it's obviously not ideal when you're targeting something more like 30 - 40 fL. That's just the affect that ABL is going to have, even on a nice plasma TV like the ST50.


I'm sure you already know this, but reviews indicate that the overall best setting for your TV (the best compromise between color accuracy and peak luminance) is cinema picture mode with contrast maxed. But FWIW, ABL doesn't seem to be affected by increased peak luminance (a higher contrast setting) in a desirable way. What I mean by that is that raising your contrast will almost certainly not make ABL less severe. If anything, I would expect ABL to become more noticeable on a plasma when peak brightness is raised, because an increase in contrast should raise peak brightness by more than it raises the level of white on a mostly or completely white screen -- and perhaps that is why (IIRC) you noticed ABL less in cinema mode than in other picture modes (?).

FWIW, I don't think your TV is defective or out of spec. I think you are just being introduced to ABL.

I don't think this is abnormal either.

I'm very, very happy with my VT50, but when a commercial ends with an all-white screen there is very dramatic drop off in peak brightness and, I'm sure, contrast. Because the only time I really notice the effect is on the tail end of commercials (which I rarely see for more than an instant thanks to DVRing), it's not very important to me.

I'd say I might feel differently if I was a hockey fan, but (a) I'm not a hockey fan and (b) there is currently no such sport played at the major-league level in the United States anyway.

I appreciate you taking the time to analyze this with me. I was under the impression that this is just how plasmas tend to operate, but when people tell me it's barely noticeable on their model or not to that degree, it makes me wonder. My brother owns an ST30 and he doesn't even have any idea what ABL is, he said he couldn't notice anything while watching someone skiing on a mostly all white screen. The review you showed me earlier that claimed it has more aggressive ABL said that it still shouldn't even really have an impact on anything but the brightest of commercials. Therefore, I'm finding it hard to get an accurate description of what ABL really does. Never the less I'm definitely going to get rid of it, whether or not it's normal, it's certainly not something I can live with. I also understand that making the contrast higher makes the ABL worse. The higher the contrast, the more noticeable the dim in luminosity is going to be. The problem for me isn't noticing the ABL though, it's the fact that the picture dims to an unacceptable level of brightness (IMO). For me, putting the contrast low enough that the screen dimming wouldn't be noticeable is counter-intuitive.

An almost completely bright white commercial would be one thing, but it literally affects everything I watch, semi-bright out door environments, cartoons such as Family Guy that are bright and colorful, and any video game taking place in a daylight setting are all noticeably dimmed. One minute the picture is bright, crisp, clear, and the next it looks dull and faded to me.

Sorry I didn't see your reply. I completely agree that turning the contrast lower is unacceptable, I like to look at a nice bright display. Again, could take commercials and near solid white images being affected, but it's certainly not limited to that for me. Of course if I watched Hockey and played hockey games that would be a different story. Yet it still affects nearly any game I play that is brightly lit, Skyrim, Assassins Creed 3, and Halo 4 all suffer from a drop in contrast to the point where they look dull and lifeless. In dark scenes or game environments the set looks fantastic however. As far as television goes I would have to say the only thing that doesn't suffer from being dimmed is either a picture with many solid colors and blacks or a mostly dark image.

I really don't know what to do at this point. I generally enjoy a bright display, but I do like the TV other than this glaring issue. I'm willing to learn that I don't need my retinas scorched to have a nice picture...I can even deal with IR (which I have been, likely due to excessive tinkering with settings while in torch mode trying to get something to stick). I feel like this TV (or plasmas) just aren't for me, but then I have others saying they don't even notice ABL. And you go on various forums asking for a new TV recommendation for movies and games, you'll basically hear one suggestion more than others - the ST50. Hardly anyone says, hey heads up, if you play or watch hockey, the screen might go into this auto dimmed, low contrast mode and there's nothing you can do about it. I've seen the hockey thing complained about, but usually that guy gets eaten alive for believing ice should be bright white...i.e. the point gets missed.

For those that don't experience it, if you open a white web page window and slowly increase it's size, doesn't it turn gray? Doesn't the text within it get harder and harder to read due to do the contrast dropping?

I don't think there are many people who don't notice ABL. I don't see it kick in very often (except during commercials), but when it does kick in, you would almost have to be blind not to notice it. On an almost entirely white screen, ABL can reduce the brightness by more than 50%. It's not subtle. The reason that it's not considered to be a major problem by many people is that we just don't think it occurs frequently enough to be considered a deal-breaking flaw, considering the positive aspects of plasmas. But when the effect of ABL is visible, it does look awful.

I'm still scratching my head trying to figure out if my set was defective or if other people just don't notice the subtler changes in picture from ABL. At any rate I managed to convince Panasonic that the set was most likely defective, and they agreed to take it back with no shipping/restocking fee. I'm still not sure if it really was defective, but it was not acceptable for me in the current condition. Most people only talk about it affecting extreme bright scenes, and professional reviewers seem to agree with that sentiment. On the off chance it was defective I'm still considering a higher end plasma as an option, I'll just be sure to test it out thoroughly beforehand this time.

From what I'm reading I'm guessing it wouldn't be wise to use a bias light behind a plasma considering the ABL?

The room I watch everything in is completely dark, so should place a plasma in this room withoght a bias light if the ABL is already dimming the screen?

Sorry I feel like I'm barging in lol.

Yes abl sucks because the tv doesnt show it's full potential, but I can think of a lot of other problems that are worse like flickering brights, darks, etc etc. I've got use to it after a month.One positive is it actually helps to keep room at a consistent brightness.I have sam51e450 and have contrast fairly low to prevent over bright whites.

Maybe it's just pannies or Samsung on LG TVS they call it energy saving mode or APS lol mine would auto dim randomly and I noticed its dimming on a lot of programs guess what LG allows you to turn it off so I did lol my plasma is tons brighter and no dimming period lol

Tyrone are you talking about led lighting on bck of tv if you are here are pics of mine no APS on

I only did a quick search but it sounds like that is similar to Panasonic's C.A.T.S setting, which adjusts the ambient light depending on the viewing environment. It's a separate setting from the ABL entirely. I would be willing to bet your screen still dims on solid white backgrounds or similarly bright scenes.

Y yeah that's what I meant. Nice set friend. It doesn't look to bad I guess.

The led lighting is prefect for movies and the ladies just saying

Yis. Me LED backlighting always gets de ladies hhh

I've tried to get my backlighting as close to optimum as possible. My cinema room is painted black, but the wall behind my TV is the most neutral Gray I could find, so the D65 bias light has the best effect on the TV.

I'd deffinetly recommend a bias light if no one has tried it.

I am pretty sure it wasn't defective and it indeed was ABL.
I am experiencing the same brightness problems ruining everything else in the picture with all the video content that is not entirely dark all the way and is clearly seen if there is more than half of the screen brighter than average.
I think a lot of people doesn't notice these subtle changes in brightness resulting in other settings in picture going wrong for decreased contrast and brightness. For me it is the first thing I notice watching a plasma TV. The contrast is wrong going from one frame to other. Comparing the contrast in different frames that is. It must be as it was meant to be by movie director. The ABL ruins it. The picture can be right in a single frame but it won't be right comparing different frames in the video, especially if in succession. That is far from true lifelike video for me.
I am experiencing this with the cheapest Samsung, PS43E450. I am sure it is ABL in action, as it obviously is in any plasma. The guy from store told me ABL can be turned off with codes. Not sure he was talking about the Samsung only or if it can be turned off completely. Would be nice if it could be set to something less disturbing.
I am searching the net and going back to that guy in store some day to find the ways turning the ABL off or to a less noticeable setting.

So I think people seeing these things during white commercials only don't see these subtle things in video picture. Their perception of brightness is less objective. (Although they should see worsened pic by worsened contrast as well.)
For me the snow must be white, not gray. Although I know the gray is just a darker white and looking at it from the darkest room in the universe it could turn out to be pretty white, my brain always remembers the true brightness of the real snow.
The worst part, of course, is the limited brightness in some of the scenes, not in all scenes, making the picture's contrast wrong in those scenes. So there is no constantly right contrast in pic, the video is not lifelike.
If the ABL results would be less severe the video would be much more beautiful. So I am looking at finding the ways turning it down.

I guess it is true the most recent plasmas got this things worse.
**** the power consumption, I want the perfect picture!

Sorry for my English.

I guess this is why most of the viewers won't notice ABL results:

ABL doesn't cut in above a certain level, it is active from the off, as you can see in the piccy in the first post (click on the piccy to see a larger version). You can test any plasma by doing a Quick Profile and looking at the RGB Separation graph.

If ABL cut in at a certain level the effect would be very obvious. Making it active from the off reduces the impact the ABL has on the viewer.

Copied this from http://www.lightillusion.com/forums/index.php?action=vthread&forum=8&topic=42

I don't know much at all about in depth calibration, and what all that means in terms of viewing experience, but I just don't understand how most people won't notice ABL in action. Now, if "notice" were swapped with "care," I would get it...to each their own, as they say. Though I hate to use the commercial example again, but if you're watching TV, and a full white ad comes on that is clearly not white, this isn't noticed by the viewer? It's just so painfully obvious to me. More often than not, I just complaints from a former LCD owner about this followed up with a "oh, you're just used to blinding whites that have too much blue in them." This might be so, but I'm also used to the gorgeous whites on a GT50 plasma when they're taking up a smaller portion on the screen, a cloud or a white shirt, but clearly no longer look brilliantly when they take up most of the screen. Well, which white is correct then? White at 15% of the screen on a plasma and white at 100% are completely different colors, yet I'm the one not seeing things correctly?

People who buy plasmas, from what I seen, know exactly what they want and sway more towards the videophile side of the spectrum than your average LED-LCD consumer. That's why I don't get how this isn't something that is openly discussed as a glaring flaw of the technology. Yet you can hardly find a review of any LED-LCD set without some sort of heads up that light bleeding/flashlighting/uniformity issue is part of the technology. I'm awaiting a swap of my GT50 for an LG LM8600 and I feel like I know what to expect. Whether I'll be content, remains to be seen.

Sorry for the rant. I'm just annoyed that I had this great TV that I researched plenty, and in the end, it's done in by a flaw I couldn't get over. Whether it was during a hockey video game, or a KHL game, or even basketball (which was the straw that broke the camel's back for me). the TV was ignoring my settings and dictating what I was to see in more instances than I care for, and that was an exercise in frustration to me. I'm just surprised this isn't a more common gripe, is all...

But in the end, I suppose when it comes to plasma vs LED-LCD, being that there isn't a perfect set out there, it's a pick your poison sort of thing...

For me how a commercial looks does not matter to me in the least. I do know that my plasma is displying a neutral 6500k shade of white and it looks normal to me, I'm sure ABL exists on my set but to me the superior blacks, color accuracy and wider viewing angles far outweigh the minority of my viewing that could be affected by ABL. Hopefully the new set meets your expectations.

Only the least perceptive people in the world won't notice ABL.


I think most of us do recognize it as a flaw with the technology. We simply find it more sufferable than things like this. Some people just find the shortcomings of plasma more tolerable than the shortcomings of LCD. Also, the best LCDs are typically much more expensive than good plasmas. But I'm sure you can find people on this forum who have purchased a Sharp Elite or Sony 950 simply because of how much they despise ABL.


I don't really care how ABL impacts commercials on my TV either, but I definitely notice it.

All I can say is for my viewing habits, sports, other tv and a bluray now and then I have never "noticed" it but to each his own hopefully this doesn't turn into a plasma bashing thread, all display technologies have flaws.

Single huh? Not too hard to tell. All joking aside, I'm looking to get a set of these myself.

when you have a bright room and you have to crank up contrast so you can see it better it makes abl more Noticable. Lower contrast reduces abl affect.Another reason plasma works better in a room with darker lighting.

There's also the Eco power saving options that need to be turned off.

That's why I asked before if I should use a bias light. Seeing as it's less noticeable in a dark room, using the bias light might light the room up a little and make ABL more noticeable.

Bias lighting actually has the opposite effect. When I turn my LED's on, the picture magically appears to be a lot brighter and is pretty much the reason bias lighting is even used in the first place.

I'm still not seeing a hint of ABL viewing movies on Netflix, Bluray, and playing games on the PS3. My last plasma had crazy pulsating issues when blacks where on the screen and it really got under my skin. So far the brightness levels appear absolutely constant. The thing that blows me away the most though are the blacks. I think my last Panasonic was a 2005 model and that thing looks completely gray compared to the new plasma. It is just phenomenal.

good to know then, about the bias lighting.

I have a Panasonic Plasma which has brightness fluctuation. I solved it very easily. How?

The set reacts when a scene has too much light coming in and will adjust it. Not common or on a lot of scenes but a few.

On my tv, I set contrast at 70 out of 100 and brightness to 50 out of a 100. Those have not changed as I notice when you reduce brightness on the tv by a few clicks it makes a bigger impact on the picture and darkens it too much. So I found a way around.

I have a Sony Blu Ray Bdp S790 and all I did was go into custom mode on it and reduce brightness to -6 and contrast to -2. I have all the shadow detail I need still as I compared it to direct mode as well as auto.

But I noticed scenes that have the brightness fluctuation no longer have it on this setting. And the screen is nice on the eyes in a dark room. The default 0 on brightness in the player notches the brightness way too much up.I thought 0 was normal but I did get eye strain in darker rooms with the setting on the default 0. -6 is the equivalent of a minor reduction on the tv's brightness setting.

So if your tv is out of warrantly, getting a Blu Ray player that has customisation features for adjusting brightness and contrast in the player is a cheaper option than paying a call out charge to an engineer as well as a possible very expensive repair.

I know in the UK, TV manufacturers have to comply with stricter energy regulations so these tv's have these fluctuations by design.
Edited by WarrenD - 12/21/12 at 5:45am

I'm jumping in really late here and with no technical or electronic "expertise" on this issue. It's just a characteristic of my TV that is noticeable to me and that I feel detracts from my viewing experience depending on what I watch. I have an LG 50PV450 and this has been a noticeable flaw since I purchased the set. Mine is calibrated and has some good aspects as well. Natural colors etc. and while I watch soccer, golf etc on a green surface uniforms and objects look great and movies are mostly nice. But sometimes ABL kicks in obviously, and when I watch hockey even more.

One thing I've noticed in the thread is that depending on the Brand and Model there seems to be a large discrepancy in the viewers perception of their ABL impact. I'm coming to the conclusion that this is not perception but actual differences (which can probably be measured) between these sets and the impact ABL has on each. There may actually be variability within models as well. I think you (and I to some lesser degree) have sets where the impact is greater and you're not nuts or picky to be unsatisfied with the result. It's not a knock on all plasmas but some exhibit a clear flaw or defect much more than they should. Others are almost unnoticeable. In the future I'll be asking questions that address this before my next purchase.

For those of you who seem unaffected by this issue please mention your model. It might help others when making future buying decisions.