Meters to measure black levels - AVS Forum
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post #1 of 10 Old 10-20-2013, 07:08 AM - Thread Starter
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Anyone know of any affordable light meters to measure blacks? I don't want anything expensive. Just something basic so i can measure my display.

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post #2 of 10 Old 10-20-2013, 07:44 AM
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What kind of display and why would the black level matter as it is what it is? You would be better served buying a quality measuring device and the needed software to calibrate your display to get the most accurate image it is capable of producing with the tools the manufacture provides. There is no way to alter the black level other than to set everything up correctly, or pay someone to do it for you.. If you have it done by a pro (not best buy or the like) you would get it measured by a very high end meter that even full blown enthusiast would not normally purchase.
What is your end goal? What does measuring MLL do for you? What is your actual budget as "I don't want anything expensive" does not help.. is $100 expensive or $2000 or $8000?
The current entry level calibration meter is the i1 Display 3 (goes by a bunch of similar names) Calman and Chromapure are the main players in purchased software. Search the forum there are many many threads about getting into calibrations and what to buy.
If all you want is light readings I would bet you could find something more photo related that can measure light level more accurately than meters build to measure the full spectrum of color. Again you end goal would help folks point you in the correct direction.
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post #3 of 10 Old 10-20-2013, 03:44 PM - Thread Starter
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My display is a pioneer 151.

I just would like to know the mll. No big reason. Just curious. As we home theater enthusiast are about anything with this hobby.

I was actually thinking of getting the Chromapure. But not now.

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post #4 of 10 Old 10-20-2013, 04:37 PM
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I was also curious as to what my panel was actually reading, but my current colorimeter I've been told doesn't read as low as my panel goes (P50S60), so I was looking forward to some very cheap light meter that would read low enough. I currently own both an X-rite i1Display 2 LT (colorimeter) and a ColorMunki Photo (spectrometer) which I use with HCFR as my software, so buying a new meter just to get the correct MLL was not appealing to me.

Sony 32" EX400 calibrated settings

Panasonic 50" S60 calibrated settings

HTPC/Sony S5100 to Sony HT-CT150 to Panasonic 55" VT60, Sony 32" EX400, Panasonic 50" S60

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post #5 of 10 Old 10-21-2013, 02:58 PM
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Just so you guys understand what you are asking about... quite a while back I got a circa $200 light meter for measuring black levels. When the Kuro displays appeared, they were too dark for that meter to measure. Other brands and models were measurable, but were pretty close to the minimum reading that meter can make. In the last 2-3 years, displays have gotten so dark, that meter can't measure any but the cheapest plasmas or LCD TVs, and even then, only if the dynamic backlight feature is turned off on LCDs.

For measuring projectors... I've run into a similar problem. I was able to get readings at the screen initially but as projectors have gotten better black levels, I started having to move the meter closer and closer to the projector lens to get readings (which have to be recalculated to produce the correct "at the screen" readings). In the last couple of years I've been running into projectors that are so dark, even with the meter's sensor as close to the projector as it can get while still being completely covered by the light beam from the lens, I can't get a reading... well, that's not true exactly... I get a reading, but it's the lowest digit the meter will display. You can't trust that though because you don't know if the real black level is lower than the value the meter is displaying or not. So to have confidence you are reading the black level, you really have to have the meter reading at least 1 digit above it's darkest reading capability.

A meter that will measure the levels we are seeing in projectors and better flat panels today sells for something like $3300.

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post #6 of 10 Old 10-21-2013, 06:24 PM
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post #7 of 10 Old 10-21-2013, 10:12 PM
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Yeah that's what Tom said in his review. I have measured a VT60 at ~0.0014 and I've seen others do so as well, which is about what D-Nice typically measures with his Klein. I haven't been able to try my D3 on anything lower. But the D3/C6 seems to be fine for anything other than some Kuros or the Sharp Elite.
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post #8 of 10 Old 10-22-2013, 03:57 PM
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Just because a calibration meter makes a reading at a very low light level, even a consistent reading, that doesn't mean the reading is accurate. Often specs are stated in such a way that low light readings can be a factor of 10 "off" from accurate. These are colorimeters, not light meters. They are measuring red, green, and blue light. When you measure .001 fL for a black level, you are measuring blue like at a level of .00007 fL which is HIGHLY unlikely to be possible. Red light will be measured at a level of .00021 fL and green will be at .00072 (approximate values, and assumes black is "neutral" and does not have an excess of either of the 3 primaries. Photometers can measure light at much lower levels.

Any by the way, when you are measuring light levels as low as the ones quoted in this thread, if you are measuring the black level in a basement at midnight with no moon, blocking the window with a light-proof covering should change the reading. A single LED illuminated in the room will change the reading you are getting even if it is not in the meter's field of view (assuming the meter is at least a few feet from the measurement surface).

Unless the meter has been verified with a highly accurate light meter (that likely will not read in the same units as the colorimeter, so the measurements will have to be converted from the photometer's units to fL to make a valid comparison), I wouldn't trust any readings lower than 10x the meter's lowest specified measurement level. So if the meter specs say .001, it is probably trustworthy to .01 unless it has been verified at lower light levels with an accurate meter capable of measuring very low light levels.

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post #9 of 10 Old 10-22-2013, 04:36 PM
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I know Chad B uses the C6/D3 for black level and contrast ratio measurements. I'm also quite sure it is accurate down to 0.001 fL for Y readings. A light meter like the LS-100 would be ideal for black level measurements (or something like a Klein K-10), but the C6/D3 can definitely do much better than .01 fL.

Also, if you use the meter in contact mode for flat panel displays, ambient light is less of an issue (dark room is still advisable though... but a single LED won't change your readings).
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post #10 of 10 Old 10-22-2013, 04:57 PM
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In contact mode, my D3 is barely (if at all) affected by ambient light. My ST50 measures the same 0.009cd/m2 in a dark or semi-bright room.

I also think that Tom knows these meters as good as anyone and wouldn't publish such findings if he didn't trust them himself.

I don't question that a dedicated light meter would be more accurate and more capable, but I think for the purposes of measuring MLL or luminance, it's close enough, as long as it's within the D3/C6's range.
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