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Samsung Cell light questions - plasma tech

post #1 of 10
10/31/11 at 8:00am
Thread Starter 
I've seen quite a bit of back and forth on it, and a interesting discussion this AM on AVS.

Here is what I've experienced with my D7000:

  • Lowering contrast below 90 results in 10pt controls acting strange. This can be overcome, but they don't respond as they should
  • I've always kept Cell at 20, from my reading, but Im not sure if there are any cons to lowering it
  • Cell 20 and Contrast 95, the set looks good but is a tad bright
  • If using Contrast, say 75, during 10pt, adjustments at 9 affect 10, adjustments at 8 affect 9, and so on. Controls at 50 have little affect, then 1-4 act as they should.


This AM, a THX calibrator, who just got a D8000, kept contrast at 95, and lowered Cell to 13, which gave him 35fL but allowed for 10pt to continue to work properly. This is a good idea, if wanting less light, unless there is something to Cell where it should not be lowered.

Any thoughts?
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post #2 of 10
10/31/11 at 9:13am
Greetings

You realize that the 35 fL number is a red herring? It doesn't matter if it is 30 ... 35 ...40 ... 45 ... and that is taught in the class too. THX recommended 35 .... based on assumptions that don't often apply in most people's homes. THX calibrators should not be arbitrarily setting the TV to 35 fL ... unless they were not listening in class.

The slide set in the class also says what I just said.

Regards
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post #3 of 10
10/31/11 at 9:17am
Thread Starter 
Understood on all. And he did not mean it that way either, it's perfect for his room. 35fL would probably work well for my room too, which is why I am curious, but up until now Ive kept both Cell and Contrast high due to past history, which leads back to my first post.

Is leaving Contrast high and reducing Cell a "better" way to reduce fL because 10pt behaves like it should? Or leave Cell high and reduce Contrast, just going in knowing that 10pt will act differently.
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post #4 of 10
10/31/11 at 9:23am
Greetings

As 34 is not perfect for his room nor is 37? biggrin.gif He wouldn't be able to tell and neither would you or me. The 35 fL is based on a black room and a specific viewing angle of the TV ... and done using specific test patterns that you or I do not have access to.

If you use the wrong patterns and set the TV to 35fL ... you have not met this THX recommendation at all.

As for the controls ... if the result is the same at a setting of 20 on the cell light, what difference does it make if the 10 point control is not perfect? It makes no difference ... to the measuring instruments in the calibration process ... you won't somehow magically see a difference with your eyes either. smile.gif

It's like debating if 13+7= 20 is a better way to get there than 10+10=20 ... or 15+5=20. biggrin.gif

regards
Edited by Michael TLV - 10/31/11 at 9:42am
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post #5 of 10
10/31/11 at 9:43am
Thread Starter 
Michael,

I understand what you are saying, as I've been told it before by Gregg. You are getting hung up on the 35fL, which has little to do with the actual question and not my intent in the first place. But since it bothers you, obviously, let's go a different route:

Here is what I know and have read about the Samsung plasma:

  • Cell light should remain at a high to max level, per many calibrators and Samsung engineering
  • When contrast is reduced below 90, 10pt controls lose their effectiveness for fine tuning, meaning I can dial in better results if Contrast is 90 or higher

With those two being thrown out there, why is it that Cell needs to be high? And, if reducing Cell to lower light output allows you to keep Contrast high, then why not do it that way? Many of the published numbers for Samsungs are Cell 18-20/Contrast 95-96. One would ASSume smile.gif Contrast is kept higher by calibrators for 2 reasons:

1) 10pt works better
2) most people need the light output

Noone has approached what you do if you have a dark environment, or don't care to squint your eyes on bright scenes. Do you just not reduce Cell? Thats all Im asking. Is Cell a setting that can be reduced instead of Contrast, and if not, why? I'm not even sure why Samsung and Panasonic have things like "Cell" and "Panel Brightness".


Thanks.
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post #6 of 10
10/31/11 at 9:54am
Greetings

The Cell control was put in not because it needed to be put in ... but because Samsung wanted to keep the same menu structure on all the TVs across their line up be they LCD or Plasma. Since Plasma did not have a backlight control ... it was easier to adjust that part of the software to make it a cell light than to completely eliminate it from the menu system. It was also somehow good for marketing. Panasonic has something similar in their custom section called panel brightness.

Sure it does things ... but our samsung contact just told us to set it at max. and not worry about it.

I am not concerned about published numbers ... because published numbers are worthless. No better than the preset numbers in the tv. You should also not concern yourself over someone else's numbers.

If you absolutely must have the 10 point system work perfectly for you ... and your imperfect instrument biggrin.gif ... then set contrast to where it does. I'll continue to follow the advice of my Samsung contact and calibrate the normal way ... adapting along the way when the controls don't work as intended. That's nothing new in this industry and hasn't stopped the good calibrators from getting the best out of the displays up to now.

Regards
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post #7 of 10
10/31/11 at 10:02am
Thread Starter 
Thanks.

I've calibrated my Samsung now, in the area of 20 times, trying many different combinations. One of them never included lowering Cell from 20, and that's why his approach was so interesting to me, hence this thread. 10pt with a Contrast in the 80 range is tricky, but as you said, can be overcome for a great result. My thinking was, if lowering Cell is feasible without creating a more significant problem than testy 10pt controls, that it is a solution that allowed Contrast to stay high when needed, in turn making 10pt work better.
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post #8 of 10
10/31/11 at 10:29am
Greetings

There usually are not any light output issues when starting with the max cell light setting. This is a plasma set after all and when has a plasma set been too bright after a calibration? smile.gif If the cell starts off making things too bright ... that gets compensated for immediately by the contrast control anyway when one follows the rules for setting contrast.

On the Panasonic, when people changed the panel brightness to high, it actually prevented the display from giving any reasonable gamma curve.

It is your TV after all ... so play with all the combinations of cell light/contrast ... 1-5-10 ... or higher ... if you want the learning experience. Don't delude yourself into thinking that one magic combination here will somehow give you 120% performance over the others. Once results get into the range of "beyond human perception" ... pushing further tells me that image quality no longer matters to the person and it is not about the movies ... but a purely academic exercise and nothing more. An exercise using a imperfect measuring device to boot.

My Jeti is imperfect ... my CS 200 was as well. Gregg's PR 670 is imperfect ... a CS 2000 is imperfect ...

Regards
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post #9 of 10
10/31/11 at 10:37am
Thread Starter 
Understood.

Part of the fun of owning a meter and talking with guys like yourself, is the experimentation. Too many people frequent forums and say "don't do this and don't do that, do this and do that", without ever once offering reasoning or evidence (not you of course). I tend to be the type of person to ask a lot of questions, as well as doing things I'm told not too (I call it wet paint syndrome; I have to touch it) because I like to see it myself, as well as learn.

I'm still amused the function was just not left in and grayed out. Ah, marketing...

I also understand imperfect. Whats really amusing, and I'm guilty, is spending xtra time on 10pt adjustment, other than gamma, to reduce a grayscale dE from 2.5 to 1. Like we can see the difference smiley_wink.gif The gamma and grayscale of these Samsungs is pretty darn good after a simple 80/20 White Balance adjustment.
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post #10 of 10
10/31/11 at 2:27pm
Quote:
Gregg's PR 670 is imperfect

Hey! ...mine IS perfect. WOWOWOWOWOWWOWOW

tongue.gif
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