[Warrior668]

I have a Samsung PS58B850 Plasma. (European Model)


My Gamma falls from 2.37 at the lover end of the greayscale to 2.15 at the higher end of the greayscale.


My Service Menü settings are:


Gamma: 0.90

Sub brightness: 128

Sub contrast: 132


In the Service Manual the basic settings are:


Gamma: 0.93

Sub brightness: 128

Sub brightenss: 128



Should i try to set it that way?


Could i get a more linear Gamma this way?



Thanks.

 

[jdoostil]

dont forget about the gamma controls in the UM

 

[Warrior668]



Quote:
Originally Posted by jdoostil /forum/post/18218170


dont forget about the gamma controls in the UM

I know, but i can´t get a flatter Gamma via UM.


The Gamma response is similar to the B650 reviewed by Tom Huffman: http://www.displaycalibrationonline....lasma_2009.asp



So, should i try to chance the settings in the service menu, is it a waste of time, could i even make it worse or will i have to find it out for myself?

 

[glaufman]

Why don't you post graphs to help us see the situation?

 

[Warrior668]



Quote:
Originally Posted by glaufman /forum/post/18220970


Why don't you post graphs to help us see the situation?

I know, it sounds strange, but i can´t find the HCFR chc files anymore.

I did the calibration over 6 months ago.


I will do a recalibration in the next weeks. (That´s the reason why i ask my questions now)


I can post the graphs afterwards, if you like.



P.S. This gamma measurement looks simliar to the one i got: http://www.avsforum.com/avs-vb/showp...2&postcount=44

 

[thomasl]



Quote:
Originally Posted by Warrior668 /forum/post/18215542


My Gamma falls from 2.37 at the lover end of the greayscale to 2.15 at the higher end of the greayscale.

Assuming that you've set brightness and contrast optimally, then that is not bad performance - the difference from one end to another is only .12 and assuming it's a smooth line down from the low to the high end, then that looks pretty good to me. My guess is that the Samsung gamma service menu setting is simply a base offset from which the user level gamma setting is based off of. What you're looking for is a 11 pt grayscale/gamma adjustment control and I don't believe any of the Samsungs flat panel plasma/LCDs have this. The one thing I'd try if you really wanted to try and get the high end gamma measures closer to 2.35 would be to experiment with lowering your contrast a bit and re-measuring to see if that improves things. I do have a Samsung LCD that when it's contrast is set above 80 - even though all the other rules for contrast are satisfied - has a gamma that begins to drop off - with a setting of the low 90s, it drops off from 2.3 at 30% to 1.9 at 95%. Setting contrast somewhere below 80 seems to flatten it out. Like with most things with consumer displays, it is a trade off that one must make.


Hope this helps,



--tom

 

[Warrior668]



Quote:
Originally Posted by thomasl /forum/post/18221765


The one thing I'd try if you really wanted to try and get the high end gamma measures closer to 2.35 would be to experiment with lowering your contrast a bit and re-measuring to see if that improves things.

Hope this helps,



--tom

Thanks, i will give it a try.

 

[PlasmaPZ80U]



Quote:
Originally Posted by Warrior668 /forum/post/18220447


I know, but i can´t get a flatter Gamma via UM.


The Gamma response is similar to the B650 reviewed by Tom Huffman: http://www.displaycalibrationonline....lasma_2009.asp



So, should i try to chance the settings in the service menu, is it a waste of time, could i even make it worse or will i have to find it out for myself?

The gamma settings will only move the average gamma up or down. Unless you want to alter the avg value from where it is now, there is no point of changing anything in the service menu. I have the B650 LCD, which also has a somewhat nonlinear gamma and I did use M_Sub_Gamma in WB Movie of the service menu but I did so to get a 2.30 avg gamma and not to flatten the gamma response. M_Sub_Gamma offers finer control than Movie Gamma or simply user menu gamma. My gamma response looks like this (see below). Note that the reference line is at 2.32 instead of 2.22, since 2.32 to 2.35 gamma is considered reference based on this source .