MacBook Pro flicker (pixel-walk issue)

Discussion in 'MacBook Pro' started by shnn2011, May 17, 2014.

  1. shnn2011, May 17, 2014
    Last edited: May 27, 2014

    shnn2011 macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #1
    I have been told by apple engineers that there will be no fix for the pixel walk issue in many MacBook Pros, and and in some of the earlier Retina models models.

    The issue seems to be from improper tuning (power regulation) to the LCD panels at a hardware level.

    Most of the newer models seem to have at best minimal issues, but on many of the older models it is quite pronounced.

    To see if your model suffers from pixel-walk please see this test: http://www.lagom.nl/lcd-test/inversion.php

    This may not be an issue for many people, but for people who work in the dark, and have sensitive eyes, it is quite annoying, especially considering that Apple had promised a fix to this via software updates.

    In my particular case I was promised a fix to the issue Less than three days after I purchased my Mac, only to be told now that I am outside of the return period, and that there will be no further fix on the older models.

    I am currently speaking to the customer service departments, and I urge anybody else who has this issue to speak with them and bring to their attention that this is not something that they are happy with, if it is as annoying to them as it is to me.

    Also, if any users have come up with a DIY fix to this problem please post it.

    Thanks

    See also:

    http://www.justinfx.com/2011/12/05/apple-macbooks-and-unexplainable-lcd-flicker/
    http://apple.stackexchange.com/ques...l-walk-screen-test-truly-indicate-a-problem-o
    http://hintsforums.macworld.com/showthread.php?t=115301
    http://forums.macrumors.com/showthread.php?t=1162962
    http://forums.macrumors.com/showthread.php?t=1388740
    https://discussions.apple.com/thread/2645516?start=0&tstart=0
    https://discussions.apple.com/thread/3089024
    http://forums.macrumors.com/showthread.php?t=1139928

    ************************* Update ***************************
    The stated reason they are calling it expected behavior is because they falsely believe it is a display refresh issue and or are trying to pass it off as one.
     
  2. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #2
    Those links are to 3yr-old posts.....yep I guess you would be "outside the return period" on a 2011 MBP.

    Scrolling causes all sorts of effects like that as thin lines move across pixel rows, I really can't see a "problem" let alone what would be the fix except higher screen resolution to the point where it becomes impossible for the eye to resolve the flicker.....

    TBH screen technology used to have way worse problems, get over it and be prepared for the day when your eyesight starts to degrade to the point when you won't notice or care (maybe by the time you are 25-30).
     
  3. shnn2011 thread starter macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #3
    Not true, some of the models sold as early as this year (2014) had really bad issues with pixel walk. Otherwise, I would not be complaining. Further, as I stated in the original post, I had paid over $200 for a screen upgrade to the highest resolution they had available.

    There are many LCD manufacturers such as AOC (who makes LCD panels under various other brand names) that have the same resolution screens (or even lower,) but have properly configured and or designed their devices to not have this issue.
     
  4. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #4
    Which bit isn't true? Those ARE 3yr-old posts so get some more recent indications of an issue and it might be relevant. I still can't see any issue to be worried about, if your have some more recent reports lets see them.
     
  5. shnn2011, May 17, 2014
    Last edited: May 17, 2014

    shnn2011 thread starter macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #5
    Your assertion that I am only talking about the older models is simply unfounded, however I see your point, in that I did not mention in the original post, that many of the late model Macs are still suffering from the issue.

    As a matter of fact two of the Apple store managers went around photographing the issue in an attempt to forward it to the engineering department after I pointed out to them in-store not too long ago.

    They were actually quite upset about the issue. Some of the models that they tested (which had the issue) are still being sold today.

    Hope that this has been enough information to show you that the issue still persists today.

    If your laptop does not have the issue, consider yourself one of the lucky ones. Many of the newest retina models do not have this issue anymore as far as I can tell.

    Additionally, this issue has very little to do with resolution or pixel density.

    "in a pixel on an LCD monitor, the amount of light that is transmitted from the backlight depends on the voltage applied to the pixel. For the amount of light, it doesn't matter whether that voltage is negative or positive. However, applying the same voltage for a long period would damage the pixel. Do you remember how electricity decomposes water into oxygen and hydrogen gas in chemistry class? Similar things could happen inside the liquid crystals that are in the pixels. In order to prevent damage, LCD displays quickly alternate the voltage between positive and negative for each pixel, which is called 'polarity inversion'. Ideally, the rapid polarity inversion wouldn't be noticeable because every pixel has the same brightness whether it a positive or a negative voltage is applied. However, in practice, there is a small difference, which means that every pixel flickers at about 30 hertz. In order to make this less noticeable, pixels with positive and negative voltages are interleaved, such that on average the screen as a whole keeps the same brightness – at least for normal images. The interleaving does not work for the inversion test images, at least for the one(s) where the pattern matches the interleaving pattern of the monitor. In such cases, the monitor will flicker if the positive and negative voltages are not tuned very well. Note that the patterns 2, 4, 6, and 7 are split into an 'a' and a 'b' version. The only difference between the 'a' and 'b' versions is that they are offset vertically (2,4,6) or horizontally (7) by one pixel; which one actually flickers is dependent on how you position your browser window."
     
  6. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #6
    Nope. But then I don't and haven't worried about the scrolling performance of my MBP (2011), MBA or the iMacs that I use. There is image fluctuation as you scroll on any computer I have ever used, I simply don't see it as an issue.

    BTW the idea of Apple staff (or anyone), photographing a screen issue is just laughable, screenshots would be the way to go as they show what is actually being shown, not a camera's interpretation of it.

    ----------

    It does because once beyond your eyes ability to resolve, you simply can't see the issue as your eye will average it out. Ever wondered why there are 65million collours only in any screen made for the past 20yrs? Its because your eye and brain can't resolve any further differences in colours so there isn't any point in making screens display more.

    This at best will be a young persons issue, I suspect anyone above 25 doesn't have the necessary vision acuity to see it at all.
     
  7. shnn2011 thread starter macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #7
    You are correct about that, however the points in which the difference is indistinguishable will not be reached by display technology for many years, because of the massive production cost and the massive amount of pixel density needed.

    However this will also have to do with a person's ability to see the difference and the quality of their optics as well as their nervous system.

    Comparing this to colors is like comparing apples to airplanes. The dynamics that affect a persons ability to perceive colors have nothing to do with resolution other than blending.

    Furthermore, humans are designed to compensate for colors variations because of the fact that in this world, we have adapted over the hundreds and thousands of years due to the fact that that there are various different types of filters such as gases, refractions, reflections, absorption . . .

    Additionally the scale of which the number of colors we can reasonably distinguish varies greatly in comparison to the scale of the ability of the human eye to see pixel density.

    What you purpose is very simply an unreasonable scale relation between completely different concepts including but not limited to: Human vision capability, electronic concepts, concepts of physics, wavelength theory, and color theory. How you have managed to reduce all of these different concepts and sciences into such a simple assumption based relation is beyond me.

    I also find it a bit offensive that you would make an assumption on my age based on good vision. You don't see me making an assumption on your age based on your level of education, and defensiveness.

    Furthermore, it the level of knowledge from apple staff photographing the screens is outside of my control.

    Perhaps, if you understood the issue you would realize that it's not simply due to scrolling and it occurs even with stationary images. Apparently, you don't have any devices that suffer from the issue or are simply incapable of seeing the issue. But this does not mean that it does not exist.

    Then again maybe you're simply bored and wish to converse with someone, and this is the best you can come up with?
     
  8. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #8
    Visual acuity declines with age. My point is that visual acuity, just as with colour perception, is limited in humans, additionally visual acuity declines with age. That is a medical fact and nothing to do with you as an individual.

    Again, it will be interesting if any indication that this exists as a current problem as opposed to 3yr-old posts (one of which had minimal replies).

    Again my point was that Apple engineering cannot be swayed by photographs of screen images to determine this level of issue.

    No I am not bored, we are having a discussion. If you want unlimited agreement with anything you post then you may have come to the wrong place...
     
  9. laurihoefs, May 17, 2014
    Last edited: May 17, 2014

    laurihoefs macrumors 6502a

    laurihoefs

    Joined:
    Mar 1, 2013
    #9
    Pixel walk has nothing to do with scrolling performance. It occurs in stationary images, and scrolling would actually hide it.

    See the description in http://www.lagom.nl/lcd-test/inversion.php and post #5 of this thread.

    This is simply incorrect. Dot walk or defects/issues of the screen would not show up in screenshots.

    Were the units you tested Retina MacBook Pros? Retina scaling causes issues with the Lagom test, which should always be done in native resolution. Otherwise you may see flickering, which can be falsely identified as pixel walk.
     
  10. shnn2011 thread starter macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #10
    I personally tested:

    * MID 2012 MBP standard display
    * MID 2012 MBP hi-res Antiglare
    * MID 2012 MBP retina
    * MID 2012 MBP 13
    * MID 2012 MBP 13 Retina
    * Early 2013 MBP 15
    * Early 2013 MBP 13
    * Various different iMacs

    The store managers and AppleCare guys tested more recent models.

    The only ones that did not have the issue were some of the newer Retina models. Some of the first run Retina models had the issue.

    The issue is clearly not scaling, but pixel walk.
    Again, Apple engineers have confirmed this, but stated there will be no fix.

    HTH
     
  11. laurihoefs macrumors 6502a

    laurihoefs

    Joined:
    Mar 1, 2013
    #11
    I know the issue is fairly common with some panels, but it's important to make sure you don't get false positives. The employees of the stores or service partners may, or may not, be aware of the effect scaling has.

    Were the Retina models set to native resolution?
     
  12. shnn2011 thread starter macrumors member

    shnn2011

    Joined:
    Feb 19, 2013
    #12
    Yes

    I checked myself
     

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