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SYC
Joined: 16 May 2006
Posts: 269
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| Posted: Sun Aug 26, 2007 2:54 pm Post subject: XG's G2 and gamma |
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I followed Kenny G's procedures to calibrate XG's G2 and it works well. My question is regarding the adjustment of Bright Gain. After doing some tests, Bright Gain control should control the gamma. Gamma becomes higer when Bright Gain is lower. From the service manual, it says to adjust IRE30 to be black when the brightness is 0, but Kenny G's says to adjust IRE50. Which gamma is supposed to be correct?
I used a Spyder with HCFR to measure the gamma. I usually get a gamma around 2.4 even though I can see the difference of gamma in video very obviously. Can some one give me the procedure to measure the correct gamma with a Spyder and HCFR?
SYC
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Sun Aug 26, 2007 9:34 pm Post subject: |
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There is no correct IRE to adjust the IRE to, it is personal taste.
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dbaisey
Joined: 09 Mar 2006
Posts: 821
Location: Southern Cal LA / Seattle WA
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| Posted: Sun Aug 26, 2007 11:38 pm Post subject: |
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SYC,
Your adjusting to a procedure that gave good results for KennyG and Guys findings at that time. It will get you close but it was also a few years ago and before many of todays 'set up' colorspace levels depending if they are correct or not. You need to find what works for your 'perfect' world and sources. Try a few different things and settings as well as room ambient light. It doesnt have to be a science if you dont like what you see or record with 'your' test equip.
You have to view it with your eyeballs that are connected to your brain. If media was perfect we wouldnt be asking what DVD to use to show your room off or what HD channel to use with what HDSTB. Bitrate and everything else comes into play. The figures your using on the test equip you have I dont know about. Doug
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SYC
Joined: 16 May 2006
Posts: 269
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| Posted: Mon Aug 27, 2007 6:59 am Post subject: |
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I am a little confused. Is the gamma supposed to be 2.2 according to NTSC standard? I know many things matter the final result, but the final result should be around 2.2, shouldn't it?
SYC
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dbaisey
Joined: 09 Mar 2006
Posts: 821
Location: Southern Cal LA / Seattle WA
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| Posted: Tue Aug 28, 2007 5:01 am Post subject: |
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NTSC standard is 2.2. Pal 2.8 Doug
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CaspianM
Joined: 26 Apr 2006
Posts: 10
Location: USA
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| Posted: Tue Aug 28, 2007 2:44 pm Post subject: |
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You always do your g2 based on the source and they vary.
The best is experiment to find the best setting for shadow detail and black level for your most used source..
Raising the gamma too much cause a visible haze (lower ansi) so keep an eye on that.
50 ire works better imo than 30 if you are not using gamma bump externally.
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SYC
Joined: 16 May 2006
Posts: 269
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| Posted: Tue Aug 28, 2007 5:07 pm Post subject: |
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I re-calibrate my XG, and find that it is very difficult to overlap RGB curve for the same gamma. Bright gain control only has a little effect on gamma. So I think I need external processor which can adjust RGB seperately to get a perfect result. Thanks all of you.
SYC
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Tue Aug 28, 2007 11:06 pm Post subject: |
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I have always used my PC to adjust the gamma to suit my taste.
I've never been able to get the XG to look right on it's own.
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CaspianM
Joined: 26 Apr 2006
Posts: 10
Location: USA
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| Posted: Wed Aug 29, 2007 1:31 am Post subject: |
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I really have had no issues with directv HD receivers. Looks great.
With Toshiba HD DVD players depending on the software it seems occasionally that my blacklevel is too low by about 2-4 clicks of brightness. Otherwise looks great. I am running my XG on a 100" wide cheapo off ebay screen for now. No complain but I like slightly higher gamma in 20~30 ire range time to time with some film material.
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SYC
Joined: 16 May 2006
Posts: 269
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| Posted: Wed Aug 29, 2007 3:42 pm Post subject: |
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| CaspianM wrote: | I really have had no issues with directv HD receivers. Looks great.
With Toshiba HD DVD players depending on the software it seems occasionally that my blacklevel is too low by about 2-4 clicks of brightness. Otherwise looks great. I am running my XG on a 100" wide cheapo off ebay screen for now. No complain but I like slightly higher gamma in 20~30 ire range time to time with some film material. |
I have no issue also and mine is great also. Every amature who comes to my house always leaves with big WOW! But I like it to be perfect because this is CRTers' way: if you know it can be better, then you go this way. I am a CRT guru in Taiwan now, so I want hometheater amatures know how good CRT is.
SYC
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CaspianM
Joined: 26 Apr 2006
Posts: 10
Location: USA
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| Posted: Thu Aug 30, 2007 1:32 pm Post subject: |
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I recall my XG wasn't to happy g2 wise with htpc and gamma tweak was always a must but not an issue at least to that extent with hd rec and hd-dvd player.
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SYC
Joined: 16 May 2006
Posts: 269
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| Posted: Fri Aug 31, 2007 3:01 am Post subject: |
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| CaspianM wrote: | | I recall my XG wasn't to happy g2 wise with htpc and gamma tweak was always a must but not an issue at least to that extent with hd rec and hd-dvd player. |
Was it caused by video level adjustment? A few days ago, I re-read Guy Kuo's procedure, I found that pedestal level, brightness control, G2 are relative. Just follow his procecure and then don't have to calibrate pedestal level with a scope. G2 adjustment compensates this.
I think Gamma tweak is a must for CRT's , not XG only. Mine is caused by little red and blue hump though I have defocus a lot enough to make blue stonger than red.
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