Originally Posted by rlindo
What are you talking about? First, the human vision thing is BS and has been proven numerous times on AVS to be bogus. Second, why do you assume that a high CR means the number is being measured simply because of the 100IRE/"white" lumen level is increased? Almost EVERY product these days that has a higher CR number is because the BLACK LEVEL(0 ire) lumen level is decreased. How can anyone not understand this?
I have a pj that is over 20k:1 (JVC RS2) and to say it will burn my eyeballs is asinine as is saying it causes fatigue/headaches. If anything, lower CR projectors/displays cause me to get fatigue because the image is hazy in low APL scenes and often in mid APL scenes. I guess all those CRT displays out there that are well over 20k:1 just destroyed the eyes of people right?
For someone to say a high CR isn't desired and is actually bad is simply ridiculous.
OK, AVS is absolutely a better source for information about human vision than the science that has been used to study it so we'll just go with that!
My comments about high contrast ratios being worthless apply only to the current state of video displays where there are no displays that produce perfectly black blacks. Contrast ratio is infinity if the video display produces blacks that measure 0 fL.
It's not that you want a low contrast ratio, it's that manufacturers LIE about contrast ratio and use all sorts of tricks to make it seem better than it is. What is important is the actual black level luminace measurement - not the contrast ratio and you can't determine what the black level is from a contrast ratio number.
WAY too many manufactuters (about all of them) keep adding more and more and more light output to try to push contrast ratio specs higher. You never know how any manufacturer measures their contrast ratio -- it's all a big secret because they cheat.
You don't want a lot of light output in a dark home theater room and that's the real point. 30 fL is PLENTY for a flat panel or RPTV in a dark room. A front projector really doesn't need more than 20 fL but even those numbers are higher than I'd use. I'd lean towards 25 fL for a flat panel/RPTV and 14-16 fL is ideal for a front projector. If the display produces 0 fL blacks, these displays will all have an infinity contrast ratio -- and that would be a good thing because the black levels would be driving the contrast ratio, not the white levels.
The only GOOD contrast ratio is infinity. Any other contrast ratio number is just a lie anyway (unless it is measured by somebody other than the manufacturer). In the real world, there is ZERO useful difference between a video display with a manufacturter's specified contrast ratio of 20,000:1 or 30,000:1. Both are lies and both are achieved with video display settings you would NEVER use.
I am measuring a PN50A550 right now as I compose this message - I am not picking on this display because every manufacturer's contrast ratio claim is baloney. I measured 0% White at 0.02 fL with a Konica-Minolta CS-200 meter ($14,000 MSRP) and ColorFacts Professional 7.5 software ($3500) and a new AccuPel HDG-4000 signal generator ($1600). A 100% White window measures 33 fL the way the panel is setup right now that's still too bright, but I haven't yet decided whether using Cell Light, or Contrast is the better choice for reducing the peak white.
33 fL and .02 fL produce a REAL 1650:1 contrast ratio - and it is STILL TOO HIGH because that 33 fL for 100% white should be closer to 25 fL for optimum viewing comfort for 4 hours or so. With the peak white level set to 25 fL the REAL contrast ratio will be 1250:1 (the black level will not change, it will still be .02 fL). I will list the settings used when these measurements were made at the end of this post - these are unlikely to be "optimum" or "recommended" settings for this panel (not that the settings for this panel would be the same for some other panel - maybe they would, maybe they wouldn't). I list them just for reference.
The marketing people specify 20,000:1 contrast ratio for this panel. WHERE IS IT? How do you setup this panel to produce 20,000:1 contrast ratio when the COMFORTABLE contrast ratio is 1250:1????
The truth is, 20,000:1 is a completely imaginary number. And even if this panel CAN produce a 20,000:1 contrast ratio - NOBODY would want to watch it while it is setup to actually produce that high of a contrast ratio. The black level is 0.02 fL and that is not going to change. To produce a contrast ratio of 20,000:1 this plasma panel would have to produce a 100% white level of 400 fL. Would you watch that????? I don't think so! Not when 25 fL is a COMFORTABLE level for 100% white in a dark room. 400 fL is FREAKIN BRIGHT and there is NO WAY this panel can achieve 400 fL unless there was considerable cheating in the measurement. The black level has more control over contrast ratio than white level... but the manufacturers know they can only get the back level to a certain point. 0.02 fL for the black level is OK, but it's not setting any new standards for the darkness of a panel display of any type. How could you POSSIBLY think that this display would be BETTER if the manufacturer's contrast ratio spec is 30,000:1 instead of 20,000:1? The black level is what it is. So the only things that could be done to raise contrast ratio from 20,000:1 to 30,000:1 is to lie more, or make the peak white level 600 fL which is even WORSE.
Given that the right way to setup a home theater is to produce an appropriate luminance level for 100% white based on room lighting, AND that the appropriate level is 27.5 foot lamberts for a panel display in a dark room (THX says 30 fL, I like 25 fL even better, so I compromised at 27.5 for this example), you could have a 20,000:1 contrast ratio and have a perfectly good video display and a 1,000,000:1 contrast ratio would be even better and an infinity contrast ratio would be the best possible. But all of those require making the black level blacker and blacker and blacker. Video display manufacturters can't do that with the technology they have today, so they make the displays brighter and brighter and brighter - which is fine if you have the TV in a family area with lights on or daylight coming in windows, but in a home theater where it is dark or almost dark, peak white levels are NOT your problem for getting good images in a dark home theater room. It's all about black level in a dark room.
For that 27.5 fL 100% white level example, a 20,000:1 contrast ratio would mean the black level would have to be .0014 fL. That's 1/14th the light output this panel actually has at 0% white. Obviously the images would be better. And the peak white level would still be comfortable. But that's not how display manufacturers measure contrast ratio. They do everything they can to make the whites as bright as they can possibly be because they know that gray glow you get instead of black is going to make their number much lower.
Contrast ratio is such a lie and so misleading, it should be banished and replaced with a black level number expressed in fL or cd/m2. That's what is important, not contrast ratio.
So in the end, a high contrast ratio alone is not evil, what is evil is the industry's emphasis on ever increasing white leves to make conrast ratio numbers appear higher when the black levels are not improving. And it's also evil when misleading tricks like blanking the screen are used to overstate contrast ratio - that will never happen while viewing image content so it is nothing but cheating.
If you set every display to a comfortable reference white level, let's say 27.5 fL for a 100% white window that fills 10% of the screen area. Then measure the black level, you'd have a useful real-world contrast ratio number and most displays made today would be in the 800:1 to 2000:1 contrast ratio range (front projectors need a different standard).
A video display that produces blacks that measure 0 fL will have an infinty contrast ratio for EVERY white level... 27.5 fL or 400 fL, it wouldn't matter, both white levels would have an infinity contrast ratio. But when blacks aren't really black, everything changes and manufacturers start lying and cranking up white levels until the displays become unwatchable. Some of the new LCD panels cannot have their white levels reduced below 40-45 fL and that is VERY BAD for a dark home theater.
Settings used on this Samsung plasma while the 1650:1 contrast ratio was measured:
Cell Light 7
Black Adj OFF
Dynamic Contrast Off
Gamma -3 (produces a Gamma of about 2.4 with the other settings as listed)
Color Space Custom (too many changes to list, CMS and gray scale were both adjusted using the meter and ColorFacts)
White Balance (settings only useful if you have the same Color Space settings I am using)
Flesh Tone 0
Edge Enhancement Off
Color Tone Warm2
Size Just Scan
Digital NR Medium (does not appear to affect HD content, only SD)
DNIe Off (obviously, not available in Movie mode)
HDMI Black level - Normal
Just for fun, I changed Black Adjust to High and Dynamic Contrast to High... black level remained at .02 fL but the 100% white window was 42.5 fL compared to 33 fL with those 2 "features" turned off. So even if Samsung used those when they were measuring their make-believe contrast ratio of 20,000:1 (and 1,000,000:1 dynamic!!!!!), neither control makes the blacks any blacker - but they do make whites even whiter!