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  • spprt Level 1 Level 1

    Do you think Retina iPads and/or iPhones use temporal dithering as well?

  • Gurm42 Level 1 Level 1



    Almost assuredly. If the MBP does it, odds are the ultra-high-res retinas do as well. I feel like the first run of 4s's have far less aggressive flickering/dithering/whatever and thus are usable, the later 4s's aren't as good and everything since then has been just dreadful.


    But I didn't need a camera. I just put my face real close to the screen and moved my eyes around - same way you can see a spinning wheel clearly by wiggling your eyes or blinking. It's a stroboscopic observation. And it turned up the dancing pixels clear as day. Some friends - who AREN'T sensitive to these things - observed it as well that same day.


    Then, of course, I spent two weeks vaguely photosensitive from being that close to a retina display for that long.

  • Dovez Level 1 Level 1

    spprt wrote:


    Did you use any special phone camera settings to make the flickering pixels visible? Could you also see them with an iPhone or iPad camera?

    I think each camera or phone will need different settings to make it visible. What I found to be the key settings were camera brightness (needs to be reduced), camera focus (had to take a photo of the screen for the phone to get the right focus), and shuter speed (I noticed that with different presets the shutter speed of the phone changes). My other phone couldn't make it visible with almost the same settings. I think a real camera with propper fucus and shutter speeds and so on would be better suited for this purpose.


    I have found that there is still a lot that the phone couldn't see. If I reduced contrast slightly in the graphic card's settings, even completely white content was flickering all the time. I did see a reduction when I set the contrast to maximum but I don't know if flicker really become less or if it just became  harder for the phone to see the effect with the higher contrast.


    Also, I think that the smaller the pixels, the harder it is to detect this phenomenon and the Retina displays could make detection much harder.

  • kvoth Level 1 Level 1

    Can anyone recommend a linux laptop with a good screen?


    I can't take my mac screen anymore, I need to switch.

  • logoo88 Level 1 Level 1

    There's something weird that is happening to me. I gave my MBP to my sister a year ago. (but not the same model, a remplacement from the Apple Store).

    I tried the new a few time, since it was not the same model but still had eye strain.


    Today I tried it another time and it looks like the screen is not blinking anymore. I used it the whole day and I'm fine. It's not the best screen I've ever had for my eyes but it's ok.


    It's the first time I'm using 10.8.5, can you confirm the issue is still happening with this version of OSX?

    I don't pretend to be "cured" and I suspect it is just temporary but I would like to have your answer.


  • azure8 Level 1 Level 1

    I picked up a Blackberry Z10. I started getting headaches and feeling sick after looking at the screen for 2 seconds.


    Never had a problem with an iPhone 4s.

  • logoo88 Level 1 Level 1

    The iPhone 4S is known to be the last iPhone inducing no eye strain for people sensitive like us. (At least the first versions)

    But, you have to differenciate PWM which affects a lot of devices to the eye strain from the mac/ios (which is not PWM according to other members).


    It's been a few days now that I ve been using the MBP and I can say I'm not sensitive to it anymore. As I said earlier, it's not as easy on the eyes as CCFL, but I can use it all the day without issues. I would really like your opinion about the 10.8.5 version.

  • spprt Level 1 Level 1

    Just got my brand new iPhone 4s (8GB) - the one that has iOS 7 pre-installed. Eye strain! After 1 hour, I'm close to a headache.


    I had a 16 GB iPhone 4s for a while. Eye strain!


    But the iPad 4 is very easy on my eyes. I bought it on day 1.


    When did you buy your iPhone 4s? Or if it is used, do you know the time it has been sold when it was unused? Maybe there are really different batches or something like that.

  • LovesDogs0415 Level 1 Level 1

    I just want to confirm for you that there are different versions of the iPhone 4S for sure, presumably all pho  My husband has one that I have no significant trouble with.  I was always afraid to use it, but on a recent vacation I had to and was shocked that I could.  Encouraged by this, I went to my carrier, Verizon, and tried a 4S and a 4.  I noticed right away that they "felt" different to my eyes, but I proceeded and got one.  Noticing the difference more and more over the first few days, I got the Model and Serial numbers from my husband's machine and asked the Verizon people and the Apple people about getting one.  I even checked the internet.  Turns out that his model number, MD270LL, was made only for AT&T.  He got one of the first ones.  No one could tell me exactly what the difference was.  Apple, the least helpful, tried to tell me it was all about the SIM cards, but I tried to explain it was much more than that. Finally, they just said that different manufacturers probably use different parts.  My model number is MD276LL/A.  A, presumably for Apple.   I am attaching a link that gives information on on the model numbers.  Not much information.  

  • Kxtr73 Level 1 Level 1

    LovesDogs0415     - Mayby LED's are different.


    Here my testing of different types of backlight applied to the matrix LG IPS 32 '. Tests position 1. and 2. done 1-2 months.


    1. original matrix EEFL lamp 25 Watt (11000 K) no PWM and light dimmed by limited current - a slight burning sensation in the left eye, the right eye: severe burning and pain behind the eyes

    2. halogen 25 Watt (3200 K), and together the same halogen bulb 25 Watt + incandascent bulb 60 Watt (2700 K) - after a few days right eye began to ache (but elsewhere when using EEFL - behind in the upper part of the eye ), no burning sensation at all

    3compact fluorescent lamp OSRAM DULUXSTAR 24 Watt (4000 K) - the best light - from 2 weeks in principle there is no problem (despite the fact that it ends his life cycle after years of work - when cold there are flashes). It is the equivalent of 120 Watt incandescent lamp.

    4. compact fluorescent lamp (I do not remember manufacturer) 35 Watt (3200 K) - at once burning eyes ...


    What we get from this conclusion? What makes the difference I don't really know. Maybe light spectrum or something else. But the light of fluorescent OSRAM DULUXSTAR is the most good for my eyes.…ampaign=Idealo_GB. For sure that specific IPS 32' LG matrix is not the problem. The light is.



    I do not test any LED's so far. I'm not so much interested in it, becouse after using another LG LED monitor in few days I had problems with eyes extending through one month.

  • kvoth Level 1 Level 1

    I plan to spend my next 5 days off work and investigating which phones and computers feel good on my eyes. If anyone has any requests or ideas for how I can test out a lot, please let me know.


    In the meantime, I grabbed all of the youtube links in this thread to see what has been posted. Here's a list of all youtube links and their titles thus far.


    "HP DreamColor Display - Overview"



    "Iiyama X2377HDS - Screen Flickering"



    "Slow Motion in Slow Motion (LED vs LCD) Monitors"



    "Galaxy Note 2 LED backlight flickering - what do you think?"



    "Asus Eee PC: no PWM Flicker!"



    "LED Incapacitor"



    "LCD Monitor Teardown"



    "LCD subpixel video player - Big Buck Bunny (entire video recording)"



    "Apple Macbook Air vs Thinkpad T60: PWM"



    "LED vs CCFL"



    "Pixel Flicker and Eye Strain"



    "iMac 2011 + Dell U2410 + MacBook Air 13' 2011 flicker test (240fps)"



    "Flicker test (240fps): Dell 3007WPF vs. iMac 27' (2011)(low brightness)"



    "Hands on - Onyx e Ink Android smartphone"



    "30hz black-white flicker"



    "galaxy s3 vs lumia 920 camera"



    "Slow Motion of a Flickering Dimmable LED Light Bulb"



    "PWM Flicker on LCD - Oscilloscope Test [Full HD]"



    "LG Cinema 3D Monitor EP4 Flicker 1"



    "snow ends view"

  • ZaneFord Level 1 Level 1

    Hi Kxtr73,


    Thanks for the info. I was wondering if you or anyone else for that matter has had symptoms from plain old LED bulbs - the ones used as fairy lights etc?


    Presumably those are not dimmed at all and thus no flicker?


    What are your thoughts?




  • LovesDogs0415 Level 1 Level 1

    ZaneFord:  Happy to give feedback.  Plain old LED bulbs absolutely make my nauseous.  I get immediate headaches and feel sick for a couple of days after exposure.  A holiday party at a neighbor's whose tree was decorated with LED bulbs made me sick.  LED-based headlights are impossible to look at. I have recently encountered some kind of LED-flourescent hybrid bulb that is real trouble.  I don't know what it is, but it was in place of a standard incandesent flood light in those ceiling "cans" so common in offices and newer houses.  It made me more sick than a flourescent ever did and my neighbor has something similar that he said was LED. ???

    Bottomline, LED lights are a BIG problem for me.  I can look at my iphone 4S but not an LED light. 

  • Dovez Level 1 Level 1

    Not all light sources flicker because of being dimmed. Some of them just flicker because of our alternating current electricity.

  • Jessiah1 Level 1 Level 1

    Zane, I don't think there is much evidence supporting any LED light's that do not flicker, it is possible some of them do not however there are two reasons why they do flicker:


    1: For dimming, it is how they control brightness through technology such as PWM controllers


    2: For energy savings, knowing this means potentially all household/business LED lighting of any kind presumably is flickering. I believe but cannot provide scientific evidence that perhaps most if not all LED lighting technology is flickering in order to save on energy consumption.


    And to answer your question: Yes, all forms of LED light give me severe symptoms of migraine and Vertigo for which I am currently on Long term disability. To support my flicker theory Vs. spectrum I will share with you that flickering fire at night also triggers headaches for me starting with my eyes, these usually do not turn into the full migraine effect however it shows full spectrum natural light gives me issues when it flickers. I believe the bright white and blue intensifies the issue greatly but the flicker is a major part of the issue. Hope this helps.

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