2010 27" i7 - backlight bleed/IPS glow, a comparison and my verdict

Discussion in 'iMac' started by max777, Aug 16, 2010.

  1. max777 macrumors member

    Joined:
    Aug 3, 2010
    #1
    I just received my replacement i7 iMac. Originally returned due to backlight bleed in bottom corners and 1 dead pixel. Low and behold replacement backlight bleed/glow is identical to the first one.

    See attachment pictures...

    The second picture is for a comparison - what a screen with no backlight should look like- my 'old' Samsung 275t 27" that this iMac is replacing.

    Anyway have been contemplating returning iMac again for cash back. BUT have decided to keep it for the following reasons:

    • it's so very fast!
    • no dead pixels on this one
    • this screen is actually pretty amazing. On anything but an all black picture, it looks fantastic. Its nice and bright and the resolution is awesome. The poor backlight in corners is a minor trade off if you step back and think about the machine as a whole.
    Apple support have been very good to me, and appreciated the replacement to put my mind at ease (in a way). Sorry to people that I supported with backlight issues on this forum- looks like I sold out to Apple in the end! :apple:
     

    Attached Files:

  2. spcdust macrumors 6502a

    spcdust

    Joined:
    May 6, 2008
    Location:
    London, UK
    #2
    My late 2009 version iMac is very similar in it's backlight bleed. In actual fact, due to other various issues, namely yellow screen, it took Apple four replacement iMacs before I settled on an "acceptable" machine. At this point I'd kind of given up the will and decided the backlight bleed was something I could accept as in "real world" use It was negligible compared to the yellow screen issue. I figure that if it bugs me I'll just get the screen swapped out, under Applecare, in a couple years time when the IPS screen technology manufacturing tolerances may have improved.
     
  3. jonwd7 macrumors member

    Joined:
    Nov 19, 2009
    #3
    This is not backlight "bleed" or "glow", and has little to do with the actual backlight.

    What you see is a property of all IPS displays without an Advanced True Wide (A-TW) polarizer.

    It's essentially a viewing angle issue. I've spoken at length about this before (not necessarily sure if it was here), and the iMacs lack such a polarizer, as do nearly all non-high-end screens.

    Firstly, the camera sensor in your photo is not parallel with the screen; it is looking down on it. That's the first clue this is what you are capturing. Secondly the "bleed" occurs only in the bottom corners, and this corroborates the first point, because the bottom corners' pixels' surface normals are further from being perpendicular to the plane of the camera sensor. Thirdly, your previous screen is S-PVA, and those screens do not exhibit this "glow" at certain viewing angles, and also have deeper black levels anyway, but of course have other problems that still make H-IPS screens superior in many regards.

    To confirm this you can take an image of the screen "looking up" and the backlight bleed should suddenly be in the top corners. Also take another image of the screen from much further away, making sure the screen is parallel with the sensor of your camera.

    Also, just by viewing the screen (with black wallpaper) at many different angles you will notice the glow moving, and it appears to give the screen depth. I liken it to a glow-y virtual reality room (with no simulation loaded :p).

    So, if I'm right about all these points there is no point in worrying about whether you should have kept this or replaced it, because it's inherent to the H-IPS technology and will never change.

    FWIW I have no actual backlight inconsistencies, but I of course have the yellowing, etc. I'm getting a 2010 one very soon and selling this after repairing it under warranty.
     
  4. max777 thread starter macrumors member

    Joined:
    Aug 3, 2010
    #4
    hey thanks for the detailed info jonwd7. Should have spoken to you earlier before I went thru a replacement!

    Your IPS tech explanation is helping me to be more comfortable with my decision to stick with iMac. Yea the glow does move at different angles.. so what you talk about there agrees with me. Hope this helps other too
     
  5. jetjaguar macrumors 68030

    jetjaguar

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    Apr 6, 2009
    Location:
    somewhere
    #5
    sorry it took so long but i have pics of mine up tonite ..
    my hdd is noisy and there is some bleed on the bottom and the side
     
  6. spcdust macrumors 6502a

    spcdust

    Joined:
    May 6, 2008
    Location:
    London, UK
    #6
    I can see where you're coming from but some of these iMac IPS screens are significantly less effected than others. Across the four supplied iMacs I had I was always able to compare one iMac screen against the other (they allowed me to keep each "current" iMac and only return it once I had received the replacement). I've also had my iMac and my father-in-laws exact same spec model side-by-side and the difference between them, with regards to the "backlight bleed", is very noticeable.
     
  7. PatriotInvasion macrumors 65816

    PatriotInvasion

    Joined:
    Jul 18, 2010
    Location:
    Boston, MA
    #7
    Wow - you guys who return your iMacs multiple times are the reason why I had to pay $1,999 for my quad Core i5 27" and not a few hundred dollars cheaper.:p

    My iMac is perfect and I can live with small issues that plague the product line as a whole - i.e. a little backlight bleed or whatever

    The box was sooo heavy when I was leaving the Apple Store, I can't imagine boxing it up and going back 4+ times for minor issues that will likely be the same on the replacement model.

    Any product will have flaws if you look hard enough for them...Just enjoy it because it's a gorgeous machine:D
     
  8. alent1234 macrumors 603

    Joined:
    Jun 19, 2009
    #8
    that's apple's fault. they should explain the tech limitations and offer a cash refund the first time
     
  9. MMM.PWR macrumors 6502

    MMM.PWR

    Joined:
    Sep 21, 2009
    Location:
    Chicago
    #9
    What you say makes sense, and I want to believe you. However, explain this (from my week 6 machine returned back in Feb/March. This was one of the 5 machines I went through before getting a refund.
    [​IMG]
     
  10. Jazwire macrumors 6502a

    Jazwire

    Joined:
    Jun 20, 2009
    Location:
    127.0.0.1
    #10
    Now thats a crappy display.

     
  11. spcdust macrumors 6502a

    spcdust

    Joined:
    May 6, 2008
    Location:
    London, UK
    #11
    Well jeez, that failed HDD in the first iMac...well I should just have kept as it's a "gorgeous machine".

    Perhaps the extreme yellow screen on number 2 and even worse on number 3...well I should have settled on those two as well.

    I didn't expect an unattainable perfect machine, but one with a functioning HDD or without an extreme jaundice cast was something I was hoping for at the price Apple charge:rolleyes::rolleyes::rolleyes:

    By the way, it is a gorgeous machine, just one with a few quality control issues at the manufacturing stage.:p
     
  12. CountlovE macrumors regular

    Joined:
    Aug 17, 2007
    #12
    There is a suppose to be a fix for the screen. If you take it into an apple store, a genius can loosen the screws for the screen. If they are tightened too much, it will cause the screen to glow in the corners. I am taking mine in tonight to get adjusted. I do hope this really fixes it...
     
  13. spcdust macrumors 6502a

    spcdust

    Joined:
    May 6, 2008
    Location:
    London, UK
    #13
    Please update the results of this "fix".
     
  14. CountlovE macrumors regular

    Joined:
    Aug 17, 2007
    #14
    Well it totally makes sense. If you take a mirror and bend it then reflection deforms around the curvature of the surface. If the screen is bending ever so slightly, the incidence angle of the the screen from your head is changing. Hence if you move your head over to the right of the corner it goes away, but everything else glows on the screen. This was my original thought when I got the 2nd BTO iMac.
     
  15. ntrigue macrumors 68040

    ntrigue

    Joined:
    Jul 30, 2007
    #15
    It would appear that the 27" cannot be purchased without some bleed due to the manufacturing process?
     
  16. slicecom macrumors 68020

    Joined:
    Aug 29, 2003
    Location:
    Toronto, Canada
    #16
    Wow. Best post I've read in a long time.
     
  17. ntrigue macrumors 68040

    ntrigue

    Joined:
    Jul 30, 2007
    #17
    Excellent.
     

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