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Contrast Ratio Claims... Balloon Juice!

Last response: in Computer Peripherals
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December 18, 2006 12:04:00 PM

(Pardon my vanity... I copied this from my previous post to put a headline on it... I'm presupposing my comments on this topic are of some general interest...)

"CONTRAST RATIO" = "Ratio of light/dark on the same screen".

For most situations, the brightness needs to be turned down from the factory-set maximum. The comfortable amount of luminescence is approximately 120 nits. (1 nit = 1 candela/meter^2). The average "darkest black" most monitors can produce these days is approximately 0.6 nits. (On some models, it's .8 or .9) 120/.6 = 200 CR. Nothing impressive about THAT!

So, the makers try to be "creative" about these numbers [read LIE]. So what if the monitor has a brighness of 500? You won't normally use more than about 120 and you have to turn the brightness down to about 25%. (If the room is brightly lit or if viewed from a farther distance than normal, you can use a higher brigtness setting comfortably.)

Some of the better monitors get their "darkest black" down to about 0.2 nits. That's good. Now the "observed CR" would be 120/.2 = 600!

Therefore, what we REALLY need for CR is (a) makers to engineer their LCDs so that their monitor's darkest black is actually darker than it is presently, and (b) to post in their specs the "actual luminescence of the darkest black when viewed with normal usable brightness"..... I haven't seen that one, have you?

Think about this... if the makers got their darkest black down to 0.1 nits, and we can "use" 120 nits of brightness, that's 120/.1 = 1200!

The place to find out the ACTUAL CR on a specific monitor is to check out x-bit labs or other reviewers who do things like measure colors with a colorimeter and measure luminescence electronically. When you do that, you often find the *maximum* CR is around 400-450 and the usuable CR is 200-250. (Another way, though subjective, is to read the Newegg reviewers' comments and notice which ones claim "really dark blacks"... that's the only important measure of CR.... and at least those models have a chance of having lower black luminescence.)

I happen to like Samsung. But their claim of "2000:1 CR" is virtually meaningless... and this type of marketing is being used on most newer models. On an older model, a claimed CR of 700:1, is likely to be closer to the truth because when those models came to market the makers weren't making such exaggerated claims.

Just as claimed "response times" are mostly balloon juice, so are the claimed CRs.

(And BTW... the makers also screw with the specs on "viewing angles", too!! :D  )
December 18, 2006 3:25:49 PM

I believe you there, marketing and legal departments have a room in hell all the time.
But on the pro side I did get my Samsung 19" Widescreen 931bw which says 2000:1 contrast and 2ms GtoG on its advertisement.
So far I'm very happy with it, I have the brightness and contrast set to 50% each and no vcard gamma increase, only low "color vibrance" from the nvidia card; no ghosting at all though some old games I have have problem with the lack of wide screen resolution and haven't foudn anything in the card to automatically scale the screen.
Just love the results, Can't wait to get a monitor like this but in 20.1 or 22 inches, if its as good asthis one then I'll be happy.
December 18, 2006 3:38:26 PM

Quote:
I believe you there, marketing and legal departments have a room in hell all the time.
But on the pro side I did get my Samsung 19" Widescreen 931bw which says 2000:1 contrast and 2ms GtoG on its advertisement.
So far I'm very happy with it, I have the brightness and contrast set to 50% each and no vcard gamma increase, only low "color vibrance" from the nvidia card; no ghosting at all though some old games I have have problem with the lack of wide screen resolution and haven't foudn anything in the card to automatically scale the screen.
Just love the results, Can't wait to get a monitor like this but in 20.1 or 22 inches, if its as good asthis one then I'll be happy.


I agree with you on the 931C... should be a TOP performermer. However, the 20.1", UXGA, screens are "enterprise" class... stressing "everything except response time"... don't look for a "931C like LCD" in a 20.1", any time soon. They are more different than they appear on the surface.
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December 20, 2006 1:52:48 PM

Which monitors have the best REAL, USABLE Contrast Ratios?

The best info you could have is about "legit darkest black measure when the brightness is 120 nits". (120 is approximately what you will normally actually use.)

You could make a logical deduction based upon claimed Brightness and claimed Contrast Ratio... (However, claims >1000:1 are almost certainly "Dyanmic" [read, Phony Balony]. *Perhaps* the claim of "1000:1" is legit.... 1000 seems to be the dividing line between "possible truth" and "Dynamic, blatant exaggeration CR") If the CR is 1400, or 2000, or so, I'd divide that number by 2 for the calculation below.

Claims of <1000:1 have a good chance of being legit....

So, just divide the "[claimed] Brightness/[claimed] CR" = [deduced] darkest black luminescence.

Examples:

250/800 = .3125 nits... PERHAPS the maker is claiming ".3 nits, black", with rounding... that would be very good.

250/1000 = .25 nits... better still

Even 300/550 = .545 nits... that's not really all that bad... just average.

300/1400 (remember to divide the 1400/2) = .428 nits... that's good too, if legit.

If you care about contrast, the best candidates for this would be monitors which claim "250 Brightness and 800 or 1000 Contrast Ratio".

Bottom Line...
1. Brightness claims >250 are usually irrelevant.
2. Contrast Ratios >1000 are also usually irrelevant.
3. Rather than focusing on monitors with the "highest brightness/CR" as the marketers want, you'll likely do better by focusing on monitors where the claims are more moderate... at least they have a chance of being legit as well as perhaps revealing an honest "darkest black" luminescence value.
4. Remember this is an attempt at DEDUCTION... you can't totally rely on marketers telling you the truth any more than you can the Gummint.

Happy hunting... :D 

PS... for david_uk... DO NOT READ THIS POST... I know how you hate technobabble (though this isn't really technobabble, just arithmetic) :D 
December 20, 2006 8:56:09 PM

Hehe. I maybe a virgin at technobabble but you are right Hose. The Bestbuy exployee who showed me the 90gx2 was saying the same exact thing. Anything over 1000:1 and brightness over 250-300 is a marketing ploy. He said in all honesty that 800:1 is great and anything above it is false.

He showed me the NEC gx2 in action and holy poo-poo. He had World of Warcraft on it (hehe dont ask). The colors looked great and the monitor looked great as well. The gloss bothered me a little but he mentioned in a not so bright room it is the best. Besides if anyone has ever been in BestBUy its sooooo bright in there. If the lights were out, the colors are incredible. He brought the monitor at eye level and covered the monitor into darkness. plus the viewing angle is phenomenal. You could be at the side of the monitor about a couple of steps back and you get a beautiful picture. Basically it comes down to your system. He basically said also, that his monitor has 6ms response time (Playing World of Warcraft) and my system if I get the gx2 also would kick his (systems/picture) rear to the curb. He also said it about the vx922. Only issue he said would be the FPS's that require fast turning and firing would be better on a lcd with 2ms response time but other than that 4ms and 2ms isnt noticable and the specs are basically identical with the vx922.
January 8, 2007 10:41:32 AM

LG has announced a new 22", 5ms gamer's model, boasting "3000:1 Contrast Ratio".... of course, that's Dyanmic, and of course, it's just more balloon juice.

It's beginning to look like the first maker who has the onions to claim "1,000,000:1 CR" is going to put everybody else out of the market...
January 8, 2007 6:43:55 PM

It'd be interesting to see if anyone has critically examined the true contrast ratios of the larger high end HDTVs from Samsung, Sony, Sharp, etc..

I know some of those 40-46" LCD screens boast upwards of 6000:1... are they really any better than PC monitors or is the balloon just filled with even more hot air?
January 8, 2007 8:10:37 PM

Nope. Same old, same old. However, you shouldn't concern yourself with it. Even in a movie theater the greatest CR you'll probably ever experience is <500:1.

I collected some data off of Xbit Labs website where they electronically measured "Contrast Ratio @ Nomal Viewing Luminance" (19", and larger). "Normal" is defined as "contrast ratio when brightest bright is set at a normal viewing level of approximately 100 nits". (Not all monitors on the market are in the test sample.)

The highest CRs:

1. Samsung 910N (PVA panel) = 1666*
2. Samsung 910T (PVA panel) = 1111*
3. Samsung 920T (PVA panel) = 400

What monitor has the best CR at normal luminance and still in production? ...... NEC 1970NX (S-IPS panel) @ 323!

Best of the gamer monitors with TN panels.... Samsung 204B & BenQ FP93GX, both @ 217.

The Samsung 920T got EXCELLENT reviews at Newegg. It's been out of production only a short time, so you can probably still find one. Others with high "Actual CR" are Samsung's 213T (S-PVA panel) and 215TW (PVA panel).

Samsung is about the best overall at producing good, working Contrast Ratios... but they are on PVA/SPVA panels... which are slower than cheapo TN panels found in "gamer" monitors.

* Testers suspected malfunction of measuring equipment.
January 9, 2007 7:16:54 PM

I'll definitely have to look into it more! I would guess those high numbers claimed by the 910N and 910T are resultant of test errors since they're so far above the others...

I own a Samsung 244t 24" myself; I wonder how that stacks up in reality (claimed CR is 1000:1, though I doubt it's really that high)

My question now is, how's the CR on high quality CRT tvs such as the Sony WEGA 34" 1080i tube, or your typical top of the line Pioneer Elite Plasma tv.
Since these have significantly blacker blacks than any LCD out there, I would imagine their resultant ratios would be considerably higher - more akin to what they actually claim in the specs.
January 9, 2007 7:31:20 PM

Well, TVs are different. Whereas a PC monitor is viewed from about 2 ft., a TV is usually viewed from 6+ ft. From the greater distance you can look at a display with greater brightness without giving you eye strain. So, you could have a higher CR simply because the brightness is higher. The REAL key to CR is "how dark is the black".

As in many other ways, TVs and PC monitors are different enough that they don't compare well.

I haven't seen where XBit Labs have tested 24" PC monitors as of yet, so no "Usable CR" values are available.
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