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LCD S-shaped Gamma curve

1000 Views 8 Replies 4 Participants Last post by  D-6500
I have a sharp LCD (D5U series) that I have been trying to get the gamma curve right on with little success..

It has a fairly severe S-shape to the gamma curve with the high end of the lumiance scale being the worst (80% input=about 80-85% light output).

I have the brightness/contrast set just about perfect (with Getgray & DVE) but the effect is clearly visible when viewing gray ramps from those cal discs.

The set has a two point greyscale adjustment (low/hi in service menu) but playing with this has only a marginal effect !!

Anyone have any experience, tricks or ideas ???


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I don't have any specific knowledge of the Sharp LCD PJ, but I noticed a similar effect on my Sanyo Z1. The only way to fix this was to go to a different picture preset mode. On my Z1, the default mode was named "dynamic" or "high contrast", or something like that. I switched it to the "Real" preset and the "S" shaped gamma curve went away. I would suggest trying any other available preset modes on your PJ.

If your Sharp PJ was designed as a presentation PJ then it's possible that you are stuck with the bad gamma curve.

It's not a projector !!!

It's an LCD flat panel....

All pic modes have the error although movie mode helps a little on the low end of the curve (just raises the whole curve) !!
Todd, I assume that you've read through the Flat Panel forum to see if you can find your Sharp model discussed?

Don't take this personally as I see it all over these forums. A newbie(or perhaps not so newbie) or lurker posts a question regarding issues with their audio or video display and are promptly given the "Phonebook treatment".

You know, you open the yellow pages to "A" for air conditioners only to find the entry "See 'Climate Control Systems'". So, more page flipping until you reach Climate control and find what you want.

The parallel here on AVS usually is one of the following:

1. Post your query in the proper subforum.

2. Do a forums search for the information you need.

It has also happened to me and I think it is a little bit of a brush-off to handle questions that way - even though it's probably unintentional.

At least someone isn't going into "Display Calibration" for advice on setting surround speaker levels, or, going into "Room Construction" for color temperature questions. Well, we are human, so I guess it is possible!

I'd rather handle 3 or 4 flat panel up- or down-converting questions daily than just tell them to search for their brand on the forums. Look at it this way - by repeating yourself it's like a review and refresh of your own skills. :)

Perhaps a huge "Search before asking:" query box should be placed in the center of the avs homepage so visitors can do such searches before delving into the forums. Users don't always know to use what isn't apparent or "well lit" to use a hokey expression. :D
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I have searched high and low for months on AVS and elsewhere with no luck.

Not even the so called pros seem to know much about these Sharp LCD's !!!

I consider myself fairly advanced at this stuff for someone who does not Calibrate tv/pj's for a living. I use a Sencore and spyder2 colorimeters for most of my own setups (friends too) with usually great results (my Sony direct view HD CRT is awesome after all my tweaking). Perhaps this is why the Sharp LCD (bedroom set) drives me nuts that I can't make it "right"....

Anyway I thought I would post in this forum to see if anyone had a cure for the s-curve issue since many LCD sets seem to suffer from this.

I'm beginning to think that short of Sharp engineers, I have more experience with all the peculiar issues of the Sharp service menus than even the ISFer's hanging around these forums ??? Hope not though..


P.S. If anyone has any doubts, this IS a calibration issue and one that should or could only be resolved in this forum !!
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D-6500, I appologize for the "brush-off", it certainly wasn't intended that way. That's why I worded my comment as a question. I see an awfull lot of relative "low-post" members who post questions without doing any looking or prior knowledge. I guess I should just keep my mouth shut, instead of trying to be of some help.

What's interesting is that I just got through reading the Home Theater Magazine's comparison of 3 LCD flat panel displays, one of which was the Sharp Aquos LC-37D40U. It also had a weird, non-linear grayscale shape and they said they could not calibrate it. They did say that it had the best picture of the 3 units compared.

This is definitely a calibration issue and apparently Sharp feels that you shouldn't be able to properly calibrate it. I am disappointed that Sharp is taking that kind of approach with their displays. I'm sure that they have their reasons, but it sure isn't obvious to me (or you). Have you tried communicating this problem with Sharp? They used to be responsive to customer problems with their displays.
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Thanks for the post Claus..

I have talked to Sharp but they have no response to my issue.

I'll have to read that Home Theater review on the new Sharps.

Todd, they don't care about your issue.

All they care about is your money, which they now have quite a chunk of.
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