27" iMac display question - is this normal for led displays?

Discussion in 'iMac' started by instabusto, Nov 21, 2009.

  1. instabusto macrumors member

    Nov 21, 2009
    This is my first led-backlit display and the first big glossy display I have used. First of all, the display is amazing because of how accurate it is and I love using it. Then to the question:

    The display is sort of alive, stick with me i'll try to explain it as best as I can, english is not my native language :p
    It kinda makes this very little brightness pumping that old crt tv's and monitors did. Same kind of effect but in a lot smaller effect, but you can sorta notice it's there. I have had none of those display image disappearance/flicker problems at all, display is working very well but I'm wondering if this kind of effect is normal with LED displays and does the glossy display enhance it/let more through? I'm thinking this might add to eye strain in long use but not sure(just like crt's did).

    Someone mentioned in another thread something about "pulse width modulation of the LEDs." but my technical knowledge of led monitors is zero so I don't know what that looks like in real life and do not know if this is that. Sorry for the very vague explanation but I dont know how to explain it better. Please chime in :rolleyes:
  2. instabusto thread starter macrumors member

    Nov 21, 2009
    Anyone else noticing the same coming from a matte lcd to a glossy led one?
  3. chrono1081 macrumors 604


    Jan 26, 2008
    Isla Nublar
    i've never seen this and my monitor doesn't do it. You may have a defective display : /
  4. iWoz macrumors 6502a


    Jan 12, 2009
    East Midlands, U.K
    I had an issue with my 27 iMac... I white line intermittently flashed across the screen.

    Had it replaced and is now fine.
  5. instabusto thread starter macrumors member

    Nov 21, 2009
    I don't have any lines or that on/off flickering, it's more of a "very minor brightness pump" and has something to do with the backlighting but i don't know if it's a fault or character of this display. I have also gotten some eye straing after using this computer for the weekend, the kind of eye strain i never get from my matte screens.

    What do you guys think, will apple take it back and give me a refund if I'm just not compatible with the machine? I ordered it from their webstore so there was no way for me to 'test' it before it got here.

    I also think one thing I could say is they marketed it wrongly when they said you can use it as an external display, they shouldve also said the actual imac has to be powered and in os x to use it as an external display(isnt this the case?)
  6. frenchie0101 macrumors 6502

    Jul 3, 2009
    you can use the 27" as a standalone monitor (i think thats what you trying to ask)
  7. instabusto thread starter macrumors member

    Nov 21, 2009
    Ok just to be clear: you can use the imacs display as a stand alone monitor even if the computer is otherwise shut down?

    I was under the assumption from reading other threads here that osx needs to be running for the imac to be able to work as a monitor to other devices.

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