Exclusive! Official JVC HD550, HD950 and HD990 Thread. News/reviews/owners
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16-10-2009, 7:59 PM
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Re: Exclusive! Official JVC HD550, HD950 and HD990 Thread. News/reviews/owners
Originally Posted by
As there is no standard to these types of tests, meters and so on, we best we can offer is a way to compare with other projectors in our testing environment, with how we perform the tests, that is the only constant and repeatable way I can think about introducing the tests.
There is a standard for ANSI CR as far as how it is supposed to be done, but it is very involved. Lots of pages with specifics about how it is supposed to be done and I think a copy of the spec costs around $100. Few people actually follow all the steps. I use different methods to try to get the true ANSI CR of the display even if not following their exact method. For instance, using a black board with a hole in it to kill most of the other light so it can't bounce around the room and hurt each measurement. I am curious about what kinds of numbers you get for your measurements given that if your values were in the 500:1+ range for the HD750 then they are significantly higher than I have measured myself or anybody else I've seen has measured.
I realize you are on the road, but when you get some time I would appreciate it if you could give examples of actual light levels you measured for just 2 of the rectangles in the center (one white and one black) to keep things simple. The ratio between those 2 numbers would be more like the modified ANSI CR that Greg Rogers does.
I can understand how people would easily measure lower than people who go to great lengths to make sure they aren't having problems with reflections in their room (like my mostly black velvet room with a black velvet board), but significantly higher has me curious as to why that might be. Are you measuring off the screen and are your black level readings far enough from the bottom of where you meter is accurate to give you good results? Are you using a color meter for ANSI CR or an illuminance or luminance meter?
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