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Brightness, Contrast, Uniformity, And Gamma

Lenovo IdeaCentre Horizon 27 Review: Our First Table PC
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Out of the box, Lenovo’s 27” touchscreen offers a native white point of 7900 K. Both the color temperature and contrast ratio of the screen also remain consistent across most brightness levels. A white point of 6500 K is considered neutral and close to the color of midday sun. If a screen measures below 6500 K, it takes on a warmer appearance that leans towards reds and oranges. If a screen measures above 6500 K, it is said to have a cooler appearance that favors the color blue. Cooler color temperatures are common in a retail environment because they make screens stand out next to other displays.

The IdeaCentre Horizon display produces moderately good brightness uniformity with a maximum deviation of 10%. Maximum brightness is less impressive at 225 cd/m2.

Color uniformity is even less impressive than maximum brightness, with a Delta E of 5.0 between alternate corners. Many people consider a Delta E of 1 to be a noticeable variation, depending on the color.

The IdeaCentre Horizon’s measured gamma response is very close to the standard 2.2 curve used by most Windows systems. A gamma response curve corrects for how the human eye is able to see light and dark colors, and large gamma errors may cause issues with editing or viewing photos. There are no gamma issues present here.

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  • 1 Hide
    Pyree , July 29, 2013 12:30 AM
    Would be nice if they have truth or dare.
  • 0 Hide
    majudhu , July 29, 2013 2:06 AM
    This explains the "for those who do" part
  • 1 Hide
    sgadadish , July 29, 2013 4:18 AM
    My only question is why not Haswell?? with all it's benefits for mobility where are the portable with the processor...
  • 1 Hide
    stupiduser , July 29, 2013 6:42 AM
    As reported on Slashdot IT - "defence agencies of key Western governments such as Australia, the US, Britain, Canada and New Zealand have banned Lenovo gear from being used in sensitive areas, because of concerns that the Chinese vendor has been leaving back doors in its devices for the Chinese Government."

    I wish Tom's would aim their incredible testing abilities at these types of claims. I would like to know if MY Lenova is making me vulnerable.
  • 0 Hide
    iknowhowtofixit , July 29, 2013 6:49 AM
    Thanks to Lenovo's horrific customer support, I won't ever have to consider purchasing a product of theirs. No, I'm not just saying this out of spite. I've had the misfortune of dealing with Lenovo dozens of times over the past few years. I can't say that I've had one pleasant experience. Now, if I have to deal with Lenovo for any reason, I'm forced to record the phone call due to the crazy amount of lying their reps are trained to do.
  • 0 Hide
    az0937 , July 29, 2013 8:00 AM
    http://forums.overclockersclub.com/
  • 0 Hide
    az0937 , July 29, 2013 8:00 AM
    http://technologygian.blogspot.com/
  • 0 Hide
    tourist , July 29, 2013 2:53 PM
    Try using this for any length of time as a table pc and your neck and back will be in knots. Not enough gpu power to really make it interesting for gamers but i can see this in industrial, medical applications, schools etc. I can see apu's being used in this application at a much lower price point.
  • 0 Hide
    Crashman , July 30, 2013 2:23 AM
    Quote:
    Try using this for any length of time as a table pc and your neck and back will be in knots. Not enough gpu power to really make it interesting for gamers but i can see this in industrial, medical applications, schools etc. I can see apu's being used in this application at a much lower price point.
    You're right, if we treat this as a huge tablet or an IPC, it looks pretty good. Thanks!

  • -1 Hide
    rcald2000 , July 30, 2013 6:54 PM
    I'm a help desk technician and I'll tell you one thing that I've learned about mobile graphics cards in all-in-one PCs; they are a very bad idea. Just yesterday I had the pleasure of troubleshooting a 4-5 year old Dell all-in-one, which had a problem with the video going black for thirty seconds at a time. I of course attempted to upgrade the video drivers, and found out that neither Dell nor nVidia had ever updated the drivers. I believe the computer originally shipped with Vista 32 bit but was advertised as being Windows 7 upgradeable. I base this opinion on the reviews that I read about the machine, and also on the fact that it had both a Windows Vista and Windows 7 logo sticker on it. Dell's site didn't have any drivers newer than 2009 and nVidia's own auto video driver detection application couldn't identify the video card. In conclusion, I think using a mobile video card in a like this size is lame. But I do applaud Lenovo for trying out new ideas. I would have more faith in the form factor if a company like Samsung was behind it. Also, I should mention that I'm typing this very review on my Lenovo X230.

    Lenovo X230
    i7 ivy bridge processor
    16 GB RAM
    500 GB 7200 rpm drive
    HD4000 integrated graphics
    * connected to one external Dell UltraSharp U2412M 24" monitor.
  • 0 Hide
    Ed Chombeau , August 3, 2013 10:38 PM
    Retired; and need big screen to see ; would take it on car travel but airline travel?
  • 0 Hide
    Crashman , August 5, 2013 2:45 PM
    Quote:
    Try using this for any length of time as a table pc and your neck and back will be in knots. Not enough gpu power to really make it interesting for gamers but i can see this in industrial, medical applications, schools etc. I can see apu's being used in this application at a much lower price point.


    Quote:
    Retired; and need big screen to see ; would take it on car travel but airline travel?
    It's about as long and wide as an oversized carry-on bag. Which means you may get it past the gate, or not, depending on how strict the airline staff is being at that gate. And you'd want something to protect the screen.

  • 0 Hide
    Marlin Schwanke , August 5, 2013 4:05 PM
    Buying budget priced gear from any Asian company is a crap shoot. I don't think Samsung, Acer, Asus or Lenovo have very good customer service. They all just shift product out the door and start working on the next one.
  • 0 Hide
    magic couch , August 7, 2013 12:43 PM
    Anyone else find it strange how in the photoshop CS6 test enabling OpenCL actually slowed down the rendering for the Dell tablepc? What's up with that?
  • 0 Hide
    Crashman , August 7, 2013 3:05 PM
    Quote:
    Anyone else find it strange how in the photoshop CS6 test enabling OpenCL actually slowed down the rendering for the Dell tablepc? What's up with that?
    Certain filters are threaded, and others are OpenCL-enabled. So OpenCL and CPU-only tests are different.
  • 0 Hide
    JPNpower , August 7, 2013 6:24 PM
    These monster screen thingies are awesome. Most likely the future (for airplane entertainment awesomeness). Reminds me of the (fake) old Microsoft Surface commercial.

    Why have a PC? Just buy a big a## table.
  • 0 Hide
    Crashman , August 7, 2013 6:45 PM
    Quote:
    These monster screen thingies are awesome. Most likely the future (for airplane entertainment awesomeness). Reminds me of the (fake) old Microsoft Surface commercial.

    Why have a PC? Just buy a big a## table.
    Maybe, but they'd need CPU and SSD upgrades to appeal to a wider market.

  • 0 Hide
    magic couch , August 10, 2013 7:27 PM
    Quote:
    Certain filters are threaded, and others are OpenCL-enabled. So OpenCL and CPU-only tests are different.

    Ahh, I thought it used both as I've seen some reviews on this website where software uses the cpu and gpu accelerated openCL together.

    Also a weird thing I've noticed is that in this article 7zip hands down beats every other program in both file compression time and size, yet in articles such as this one winrar is faster by a factor of over 2. Why is there such a discrepency? The articles are even using the same versions of the program.


  • 0 Hide
    Crashman , August 10, 2013 8:21 PM
    Quote:
    Quote:
    Certain filters are threaded, and others are OpenCL-enabled. So OpenCL and CPU-only tests are different.

    Ahh, I thought it used both as I've seen some reviews on this website where software uses the cpu and gpu accelerated openCL together.

    Also a weird thing I've noticed is that in this article 7zip hands down beats every other program in both file compression time and size, yet in articles such as this one winrar is faster by a factor of over 2. Why is there such a discrepency? The articles are even using the same versions of the program.
    The would be a great question for our developer. I think the command line switches outlined in the "test setup" page might provide the answer, but only if I knew what those switches meant :p 

  • 0 Hide
    JPNpower , August 10, 2013 8:50 PM
    Crashman, thank you for your reply in the comments for all your articles.
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