With our change to CalMAN, we will also now be evaluating displays for their grayscale and gamma point. Previously we only targeted a gamma of 2.2 in calibrations but never measured it in the end. Now we will be choosing two targets in our reviews. For light output of 200 cd/m², we will target the same gamma of 2.2 right now. 2.2 gamma is still a de-facto standard, and is the standard for Apple computers and devices as well as video content. For our second calibration we target 80 cd/m² with an sRGB gamma curve. Both of these are specified in the sRGB standard, so those doing professional print or computer graphics work would likely want this.

Hopefully a display will be able to handle both of these tests, and we will also check for the grayscale quality on its own by checking 21 points, just like we do with our tablet and smartphone reviews. This will provide you with more data, as well as consistent data for the different devices.

  Pre-Calibration 200 cd/m² Target 80 cd/m² Target
White Level 201.5 198.4 80.1
Black Level 0.1689 0.1644 0.067
Contrast Ratio 1193:1 1207:1 1197:1
Average CCT 6545 6537 6599
Gamma 2.1648 2.2128 2.4109
Average dE2000 2.3847 0.535 0.6238

Looking at the RGB Balance for the data, the pre-calibration data starts out a bit too-blue, then develops a red tint, before finally winding up with a lack of green at the top of the grayscale. The average CCT remains close to 6503K overall, but the RGB balance shows that there is a lack of correct balance in there. Looking at the post-calibrations numbers for 200 and 80 cd/m², we see almost no deviation at all in the RGB balance, which is much better. The 80 cd/m² results have a bit too much blue perhaps, but overall they're acceptable.

The pre-calibration gamma point is very close to the 2.20 target, but looking at the chart we see some issues. The gamma point rises and falls across the grayscale, which will leads to midtones and highlights not having the correct level of light output, and will lead to a less dynamic image. The overall number is good, but the chart shows that it’s not quite right. The 2.20 target for our 200 cd/m² calibration is much better, with a very linear 2.20 gamma across the whole grayscale. There are a couple small bumps in there, but nothing that would be visible in daily use.

The sRGB target is different, as the gamma isn’t linear across the whole grayscale. Instead the shadows start at 1, and it ramps up as you leave the shadows, which results in an average gamma across the grayscale of 2.40 in the end. Because of this it’s far more important to look at the actual graph than the final number, and here the LG 29EA93 does very well at tracking the target. Once calibrated, the gamma curve for the LG is very good with either sRGB or Power Law targets.

The grayscale dE2000 values takes all of this data into account. Pre-calibration, the dE2000 starts out well in the shadows, but by the end of the grayscale we have dE2000 values above 3, indicating a visible grayscale error that we can see even in motion. The average error is pretty low, but by the end it’s higher than we would like. Post-calibration, both grayscales are free of all visible error. There isn’t a single point that is above 2.0, and no one should be able to see any errors in real world use. In the end, the grayscale is basically perfect for these displays after calibration.

Pre-calibration, the LG 29EA93 is good, but not great. Post-calibration, it’s virtually perfect and will be basically free of visible errors when being used.

Intro, Brightness and Contrast Color Performance
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  • cheinonen - Thursday, February 14, 2013 - link

    Since there seems to be a lot of feedback from those worried about the fact that LG provided a new sample that tested well, I decided to add some more comments about the matter, and clear some things up.

    - The first sample was also hand delivered by LG to me. Every monitor sample I have had has been from a PR company or a company directly, and none of them have been bought by myself.
    - If it was so easy or even possible to hand-tune a sample to have the performance offered by Rev. 1.25 of the 29EA93, then wouldn't we expect every monitor that comes in for review to be that good? As it is, samples arrive that perform good and bad. You can look at the Acer monitor that was just reviewed to see it had issues (I had to manually loosen a screw to get the stand to work correctly, which they said would be fixed) and wasn't hand-tuned.
    - You can also look at my Nixeus sample that had a brightness control issue, or many other display reviews that have been published. If it was so easy to game the system, every vendor would do it.
    - Buying samples just isn't realistic. Most displays arrive for 30 days at most before going back to a company. Many arrive well before the street date so that reviews can be completed and published on the release date. This isn't possible if you need to purchase units, besides being cost prohibitive. Yes, some places would let me return them, but I have ethical issues about buying something I know I'll return, and then they will have to sell at a discount.

    If I thought what LG was doing was in any way biasing my coverage, I wouldn't do it, but what they have done as far as providing samples is no different than any other company. What is different is their taking feedback and using it in a positive way, whereas many other vendors might try to deny the findings or just cut off communications, both of which have happened to me before. Being skeptical is fine, but I find no reason to think that LG wanted to anything else other than make a better product than they initially released, and providing the display to me is not different from the normal review process in any way at all.
  • 5150Joker - Saturday, March 23, 2013 - link

    Chris, LG should provide some of us a clear route to firmware upgrades that have purchased their displays. That I think is the chief concern among many of us that are concerned about buying an older version. If they were to release the updated firmware on their website in a reasonable time frame (say 1 month from now) with an easy path to upgrade, then nobody would be worried. As it is now, there is no way to differentiate between the older and newer model. This isn't limited to this model either, the LG 27EA83-D has the same problem. A korean website (www.playwares.com) was hand delivered a tuned unit and their lag tests were phenomenal. Unfortunately, I'm one of the people that already owns the 27EA83-D and would hate to be left out in the cold w/an early firmware. LG has a responsibility to clarify and rectify this situation for its customers.
  • avihut - Thursday, February 14, 2013 - link

    I was wondering which resolutions does the screen support?

    I mean does it only support the optimal 2560x1080 at this ratio or does it have something equivalent in the area of 1920x800 or even lower. My machine won't be able to do 2560x1080 on all my games, so I want to know if I'd be able to fall back on lower res but still get the same ratio.

    Awesome review. Looks like a superb display.
  • cheinonen - Thursday, February 14, 2013 - link

    With non-native resolutions you can have them scale to fit the screen, or do 1:1 pixel mapping for them.
  • avihut - Friday, February 15, 2013 - link

    But will the ratio preserve or will I have to play in letterbox mode?

    I wouldn't want to stretch 1920x1080 on this screen, since everything will look, well, stretched.
  • SpartanGR - Thursday, February 14, 2013 - link

    How can we tell the diff between the old and the new one if i want to buy it?
  • SpartanGR - Thursday, February 14, 2013 - link

    Why can't we just firmware update our monitors? sigh....
  • sheh - Thursday, February 14, 2013 - link

    The start of the firmware-upgradable-monitor era? :) "Hey, I just overclocked my monitor using RadFirmware! Plus, scaler mode selection!"

    Why would TV-range chroma/luma affect contrast? It's supposed to be displayed expanded to the full range, no?

    What quality differences are there in game mode?

    Anyway, not the monitor for me. Waiting for some 3840x2400 24" 120Hz. OLED wouldn't hurt either, but that can wait another year or two.
  • cheinonen - Friday, February 15, 2013 - link

    When calibrating for TV/Blu-ray/non-PC video, 16 is video black and 235 is video white, as opposed to 0 and 255 with PC content. The monitor shouldn't expand this, so you're calibrating to a smaller range. You can find some devices that will expand video content to the full RGB range (often labeled as RGB Full) that would then use the 0-255 range. For standard video content you only use a subset of that, so you'll have less dynamic range compared to PC.

    The PC mode was certainly bluish, with a higher color temperature, with fewer adjustments available in order to remove processing lag.
  • sheh - Saturday, February 16, 2013 - link

    That's odd. I'd expect monitors in "TV mode" to expand 16-235/240 to 0-255, just like decent PC software players/decoders. Or maybe whatever feeds the video should do that. Or more like, either one, depending on the settings you select.

    Well, thanks.

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