CNET and televisioninfo Calibration - AVS Forum
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post #1 of 29 Old 05-17-2012, 12:36 PM - Thread Starter
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CNET webpage is doing tv reviews with calibration reports. I read that they are calibrating the TVs light output (Y to 100 IRE) approximately 130 footlamberts. This is an outrage, right?. The findings of the review will be erroneous, right? What do you think?
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post #2 of 29 Old 05-17-2012, 12:39 PM
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Please provide a more specific link to such statements.
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post #3 of 29 Old 05-17-2012, 12:52 PM
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Quote:
Originally Posted by electroFan View Post

CNET webpage is doing tv reviews with calibration reports. I read that they are calibrating the TVs light output (Y to 100 IRE) approximately 130 footlamberts. This is an outrage, right?. The findings of the review will be erroneous, right? What do you think?

It's probably cd/m^2 and not fL

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post #4 of 29 Old 05-17-2012, 12:58 PM - Thread Starter
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I'm confused
CNET first explained to me that the luminances are measured in foot lamberts. CNET Depues explained to me that the luminances are measured in cd/m2.
For example the last review of the LG LM9600 explains:
Black luminance: 0.0198

CNET 0.0198 qualifies as an average value. If the value is measured in cd/m2 then it is a very good value.

Furthermore CNET says:

To 100 IRE Luminance pre-calibration: 145.1
To 100 IRE Luminance post-calibration :: 134.3

It's strange pre-calibration luminance of 145.1 cd/m2 is not it?
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post #5 of 29 Old 05-17-2012, 01:01 PM
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Quote:
Originally Posted by electroFan View Post

I'm confused
CNET first explained to me that the luminances are measured in foot lamberts. CNET Depues explained to me that the luminances are measured in cd/m2.
For example the last review of the LG LM9600 explains:
Black luminance: 0.0198

CNET 0.0198 qualifies as an average value. If the value is measured in cd/m2 then it is a very good value.

Furthermore CNET says:

To 100 IRE Luminance pre-calibration: 145.1
To 100 IRE Luminance post-calibration :: 134.3

It's strange pre-calibration luminance of 145.1 cd/m2 is not it?

Not really, you can typically lose a bit of luminance calibrating. Typically you turn down contrast to prevent clipping. In doing that you'll give up a bit of luminance. Also moving the white point from 13000K or whatever ships from the factory to D65 may also cause the luminance to be a little lower.

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post #6 of 29 Old 05-17-2012, 02:04 PM
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Quote:
Originally Posted by electroFan View Post

I'm confused
CNET first explained to me that the luminances are measured in foot lamberts. CNET Depues explained to me that the luminances are measured in cd/m2.
For example the last review of the LG LM9600 explains:
Black luminance: 0.0198

CNET 0.0198 qualifies as an average value. If the value is measured in cd/m2 then it is a very good value.

Furthermore CNET says:

To 100 IRE Luminance pre-calibration: 145.1
To 100 IRE Luminance post-calibration :: 134.3

It's strange pre-calibration luminance of 145.1 cd/m2 is not it?

the CalMAN reports are in cd/m^2, that's just the way reporting works in CalMANv4

the (post-cal) target fL CNET uses for all displays' peak white is 40 fL
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post #7 of 29 Old 05-17-2012, 02:09 PM - Thread Starter
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I think CNET indicates the luminance at 0 IRE in footlamberts (0.0198 ftL ) and then CNET indicates the luminance at 100 IRE in cd/m2 (145.1 cd/m2).

Is this correct?
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post #8 of 29 Old 05-17-2012, 02:28 PM
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Quote:
Originally Posted by electroFan View Post

I think CNET indicates the luminance at 0 IRE in footlamberts (0.0198 ftL ) and then CNET indicates the luminance at 100 IRE in cd/m2 (145.1 cd/m2).

Is this correct?

yes, CNET uses fL in their reviews but the CalMAN reports are limited to cd/m^2 only (by design)
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post #9 of 29 Old 05-17-2012, 02:32 PM - Thread Starter
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This creates confusion, right?.

CNET should use the same unit of measurement to measure the luminance at 0 IRE and 100 IRE is not it?
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post #10 of 29 Old 05-17-2012, 02:35 PM
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Quote:
Originally Posted by electroFan View Post

This creates confusion, right?.

CNET should use the same unit of measurement to measure the luminance at 0 IRE and 100 IRE is not it?

in the report it does (cd/m^2 only for all "Y" values)

but the number in the geek box is in fL
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post #11 of 29 Old 05-17-2012, 02:45 PM
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The conversion back and for is 3.43 cd/m^2 to 1 fL.

So 0.0198 in fL is .0679 cd/m^2

A value of 134 cd/m^2 is 39 fL.

Gust to ballpark it I remember it's about 3 1/3 to one.

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post #12 of 29 Old 05-17-2012, 09:40 PM - Thread Starter
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Now I am reading the calibratión of the webpage televisióninfo about LM9600 and I see thay they have calibraed tv for light output (peak white) of 436.95 cd/m2.



What is your opinnion about it? Should not they have calibrated the TV for a light output of 30-40 ftl?

Then all their conclusions are wrong or no?
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post #13 of 29 Old 05-18-2012, 12:09 PM
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Quote:
Originally Posted by electroFan View Post

Now I am reading the calibratión of the webpage televisióninfo about LM9600 and I see thay they have calibraed tv for light output (peak white) of 436.95 cd/m2.



What is your opinnion about it? Should not they have calibrated the TV for a light output of 30-40 ftl?

Then all their conclusions are wrong or no?

IMO that site doesn't know the first thing about calibration

they set backlight to 100% and used standard mode instead of the THX or ISF Expert modes
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post #14 of 29 Old 05-19-2012, 02:07 AM
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Quote:
Originally Posted by electroFan View Post

Now I am reading the calibratión of the webpage televisióninfo about LM9600 and I see thay they have calibraed tv for light output (peak white) of 436.95 cd/m2.



What is your opinnion about it? Should not they have calibrated the TV for a light output of 30-40 ftl?

Then all their conclusions are wrong or no?

Uh.. I think that charts just to show highest contrast of those TVs, that's why they used "Peak" white ( backlight and contrast set to 100%). It isn't calibration.
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post #15 of 29 Old 05-19-2012, 02:42 AM - Thread Starter
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Quote:
Originally Posted by fallengt View Post

Uh.. I think that charts just to show highest contrast of those TVs, that's why they used "Peak" white ( backlight and contrast set to 100%). It isn't calibration.

Televisioninfo say in "How we test tvs"

Peak white:

To measure the brightest white the TV can achieve, we set the display to show a small area of white (about 4% of the screen) at the center of the screen and measure the luminance in candelas per square meter with a CS-200 ChromaMeter set for a one degree acceptance angle. We do this after calibrating the HDTV as described above. Our score is based on how bright the white is after calibration; the brighter the white, the higher the score.
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post #16 of 29 Old 05-19-2012, 04:57 AM
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Yea? they didn't say it's the ideal condition to watch TV.It's just how they test and to score the white level and contrast.
Quote:


To measure the brightest white the TV can achieve

The post-calibration results is meaningless for most people who don't have calibration tools (or don't want to hire ISF calibrators). That's why pre-calibration result is more important in a review.
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post #17 of 29 Old 05-19-2012, 05:29 AM - Thread Starter
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Quote:
Originally Posted by fallengt View Post

Yea? they didn't say it's the ideal condition to watch TV.It's just how they test and to score the white level and contrast.

They say bright white after calibration on LG LM9600 is 436 cd/m2

This is outrageous and it undermines the credibility of the review

Quote:
Originally Posted by fallengt View Post

The post-calibration results is meaningless for most people who don't have calibration tools (or don't want to hire ISF calibrators). That's why pre-calibration result is more important in a review.

All pages written reviews score tv on black level and contrast post-calibration
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post #18 of 29 Old 05-19-2012, 05:57 AM
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Quote:
Originally Posted by electroFan View Post

They say bright white after calibration on LG LM9600 is 436 cd/m2

Well, here is the ideal ... You can do peak white reading without calibration but the white may have some color tint and balance white level also change peak luminance thus result will be differents from these test methods. You can't say a blue tint white TV which has higher peak white is better than a zero color-tint white TV which has lower luminance.

What they want to achieve is to read "PEAK" white(without any tint - 100% RGB balance). By this way, the results from other TVs can be comparable from those charts.

I'm done here
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post #19 of 29 Old 05-21-2012, 08:44 AM - Thread Starter
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Calibration of televisioninfo for Samsung ES8000

Contrast: maximun (100)

Backlight: Maximun (20)

Output light: 351 cd/m2

What do you think?
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post #20 of 29 Old 05-21-2012, 10:38 AM - Thread Starter
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CNET TV's always calibrated dynamic contrast on, Is not this a mistake?
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post #21 of 29 Old 05-21-2012, 10:41 AM
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Quote:
Originally Posted by electroFan View Post

CNET TV's always calibrated dynamic contrast on, Is not this a mistake?

they don't; show me some proof to back up your claims
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post #22 of 29 Old 05-21-2012, 10:42 AM
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Quote:
Originally Posted by electroFan View Post

Calibration of televisioninfo for Samsung ES8000

Contrast: maximun (100)

Backlight: Maximun (20)

Output light: 351 cd/m2

What do you think?

don't use that site; they don't know what they're doing
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post #23 of 29 Old 05-21-2012, 10:49 AM - Thread Starter
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Quote:
Originally Posted by PlasmaPZ80U View Post

they don't; show me some proof to back up your claims

LG LM6700 LED Local Dimming: High

Sony HX850 LED Dynamic Control: Standard

LG LM9600 LED Local Dimming: Medium

Sony HX929 LED Dynamic Control: Standard
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post #24 of 29 Old 05-21-2012, 11:05 AM
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Quote:
Originally Posted by electroFan View Post


LG LM6700 LED Local Dimming: High

Sony HX850 LED Dynamic Control: Standard

LG LM9600 LED Local Dimming: Medium

Sony HX929 LED Dynamic Control: Standard

Non of those have dynamic CONTRAST on. Local dimming, and dynamic contrast, are two different things. All those links are backlight controls, at least the ones you're referring to.
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post #25 of 29 Old 05-21-2012, 11:20 AM - Thread Starter
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Quote:
Originally Posted by ElectronicTonic View Post

Non of those have dynamic CONTRAST on. Local dimming, and dynamic contrast, are two different things. All those links are backlight controls, at least the ones you're referring to.

Local dimming ¿should not be turned off? Is it proper led dynamic control this on?
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post #26 of 29 Old 05-21-2012, 11:40 AM
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Quote:
Originally Posted by electroFan View Post


Local dimming ¿should not be turned off? Is it proper led dynamic control this on?

Calibrate with it turned off.

When you view content, off or on, your choice.

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post #27 of 29 Old 11-02-2012, 01:49 PM
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They clearly state these settings on post calibration... and it's proof in there video review.

They claim the LG7600 has deep black levels... this would have only been the case if local dimming was engaged.
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post #28 of 29 Old 11-03-2012, 12:11 PM
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In any case, are you sure you can trust a source (CNet in this case) that uses "IRE" when referring to digital video? There is no such thing as IRE in digital video. IRE is an analog video specification that determines how bright the image is compared to the analog input voltage. Digital video doesn't use analog voltages to determine brightness. In digital video, "% white" is accurate and correct. IRE does not exist for digital video and does not mean the same thing as % white... it CAN mean the same thing as % white when referring to analog video, but it MIGHT NOT be the same thing as % white when referring to analog video... it all depends on how the video display is setup.

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post #29 of 29 Old 11-05-2012, 03:12 PM
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I agree, CNET seems to do some odd things when it comes to testing. Also stating that the LG7600 had good black levels while the ES8000 did not, makes zero sense.

What would you recommend as a quality source for reviews?
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