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Mark (Milori), or any other guru's...


What is it specifically about DILA (LCOS), that is holding back the z9000-like contrast numbers? Is it reflectivity of the panel, light absorbtion, or something else?
 

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Hi David,


Good question.


Technically, the "G" projectors can do 1700:1 or more contrast (full on/off). When fooling around with the Dilard Calibration Wizard, I set up parameters that "calibrated" the projector and measured 1750:1 contast (full on/off) on my G11 that has almost 800 hours on the bulb. I posted this finding on the forum immediately, as it shocked me as well.


Realistically, a really good picture quality dictates a much lower contrast setting in practice. There are many simultaneous goals, and contrast is certainly one of them. You also want whites that are smooth and pleasing right up to peak white and don't "blow out" on the top end (an oft-heard complaint on some units about "hot whites") and also accurate shadow detail in dark scenes.


Dilard actually artificially constrains the contrast on purpose through several means (including not setting the black level too low, purposefully limiting the brightness of the whites, and prioritizing accurate color over absolute contrast). The contrast usually comes in over 600:1 with this technique, but the picture looks great!


Ultimately, it's the black level that really establishes the contrast, but crushing the blacks to get the contrast number up doesn't produce a more pleasing picture (but it *does* look impressive when you see the number :p).


500:1-700:1 contrast can produce a really great picture, and indeed the "SC" designation on the projectors stands for "Super Contrast" and is an indication of a >600:1 contrast ratio. It is a completely different picture than the 60:1 to 250:1 that these projectors have "out of the box". Many other projectors can't even reach 200:1, no matter how they are tweaked.


Keep in mind that these are real contrast ratios, and not manufacturer specs. I have to wonder about the 1100:1 contrast ratio claim, and would like to measure that one myself.


I can't answer this from a hardware standpoint (voltages, optics, etc), so I hope that this helps!
 

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The sharp is a dlp projector. As such with moving micromirrors, when the mirrors are pointed completely to the off position the blacks are only limited by internal scattering due to the lenses and other effects including light reflected by dust particles. I will not mention the color wheel effects that some people see in single chip dlp projectors. The price of 3 chip dlp projectors has to come down! There is also (currently) a limit of 256 gray levels. (8 bit effective d/a)


The d-ila panels are reflective lcd panels. While these will continue to get better in the next few years, they can never be fully off. There will always be a maximum contrast ratio that cannot be exceeded. In addition biasing the panels to be as hard off as possible is not a good thing because cumulative dc offsets build up over time and cause 8 bar and or shading problems.


Neither technology is perfect. Crt's aren't either. There are however stunning new display technologies that within 5 years will make current technology partially obsolete. Can't wait.
 

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Milori (Mark),


Don Stewart reported the actual "real world" contrast numbers for the Sharp 9000 DLP. Look in the "Screens" section of the forum under "Which screen is best for the Sharp 9000"


pkurtis
 
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