Luminous Landscape Forum

Equipment & Techniques => Computers & Peripherals => Topic started by: Frans Waterlander on September 16, 2013, 07:53:12 pm

Title: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 16, 2013, 07:53:12 pm
It is reported that some people see flicker or experience eye strain or headaches when working with LED backlit monitors. This would be caused by pulse width modulation where the backlighting is switched on and off rapidly at varying on and off times to change the brightness. If this frequency of on and off switching, the pulse width modulation frequency, is below 500Hz or even 1kHz, these problems are reported by some people and not by others. Although the brightness of most CCFL backlit monitors is also changed using pulse width modulation, this is less of an issue because the CCFL tubes don't turn off completely during the off cycle, because they have some after glow, reducing the on/off contrast.
 
Here's my question: have you experienced any of these issues - flicker, eye strain or headaches - when using an LED backlit monitor and if so, which monitor did you use and do you know by any chance the pulse width modulation frequency?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Ellis Vener on September 20, 2013, 08:36:26 pm
no problems here: Apple 27' white LED backlit LCD
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: kaelaria on September 21, 2013, 04:24:44 pm
That answer will depend greatly on the specific monitor and individual person.  Each person's brain will be operating on slightly different frequencies and vary through the day.  Mine is rather quick and I see the flicker of most LED bulbs quite easily such as xmas lights.  It drives me crazy but my wife can't see a thing.  I can see it even on FL backlights but it doesn't cause me any issue, and I have never had an issue from LED backlit screen on my laptops.  For example I have used this Dell 24" for years and it's a cycle or two less than my Dell 27" - both FL.  You can see it quite easily on video, even though both are 'running' at 60Hz in the OS and rated for 60Hz by Dell equally. 

http://www.youtube.com/watch?v=M3MD6HQ18Ko&feature=youtu.be (http://www.youtube.com/watch?v=M3MD6HQ18Ko&feature=youtu.be)
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 22, 2013, 12:47:10 pm
Another non-issue (IOW, no).

The beat of other fluorescent lighting nearby, perhaps room lighting running at 50 or 60Hz could give this impression.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:03:44 am
A non-issue, Andrew? Really? Many people have issues when the LED pulse width modulation frequency is below 1500Hz or so and many LED monitors operate well below that. If by any chance you might be interested in educating yourself, I'll be happy to provide you with links to articles on this issue.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: bcooter on September 23, 2013, 09:58:36 am
Another non-issue (IOW, no).

The beat of other fluorescent lighting nearby, perhaps room lighting running at 50 or 60Hz could give this impression.


Not true here.

I blew out a left eye with a detached retina about 6 years ago and it was semi fixed, but it's very sensitive.

I can work on a powerbook screen or my 30" dell for 12 hours straight and I'm fine, but I have two new 27" Imacs, one in London, one in LA and in 4 hours both of those just kill me.

This isn't a one time occurrence, it's every-time, so I don't know physics, I do know pain.

IMO


BC
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 10:03:57 am
There you go Frans, your answer and maybe one you'll actually accept. One user here who has an issue, all those links you know of, those of us that say no issue. What is the next set of windmills to chase?

You finish that piece from the CIE that talks about how calibrating to D50 doesn't always (often not) work?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 01:22:25 pm
Andrew, You really want to compare an issue that can cause epilepsy, migraine, retinal desease, urticaria, eye strain, nausea, etc, etc. with tilting at windmills and deride me for having an interest in this issue? I happen to be considering buying the NEC P232W and it was brought to my attention on this website that it has a very low PWM frequency and might cause issues for many people, so I'm trying to learn more about it. Is that OK with you?

And since you brought up the issue of "that piece" again, let me refresh your memory: I said at the time that I would not respond to your personal attacks and nothing has changes since then. Have a nice day.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 02:20:57 pm
You really want to compare an issue that can cause epilepsy, migraine, retinal desease, urticaria, eye strain, nausea, etc, etc. tilting at windmills? And who are you to deride me for having an interest in this issue?
Point me to the source of epilepsy, migraine, retinal desease, urticaria, eye strain, nausea caused by LCD displays please.
The last two identical posts you started here and on PhotoNet resulted in your identical behavior, asking questions and dismissing anything but the answers you predicted what you wanted to hear. I suspected this third post was going to be yet another similar tactic on your part, I don't as yet think I'm wrong.  
Quote
I happen to be considering buying the NEC P232W and it was brought to my attention on this website that it has a very low PWM frequency and might cause issues for many people, so I'm trying to learn more about it. Is that OK with you?
Fine, buy the unit, and if you have an epileptic seizure, send it back or better, get a demo at a good VAR before you put down your money. If 3 out of 30,000 people here reported that yes, they had a migraine by viewing an LCD backlit display, you'd do what with that info and that would change how you purchase and return it how? And you didn't specifically ask about this NEC in your original post, you asked about LCD's in general (that's telling). Hence the comment about windmills. This is much like your flat earth theories about Solux CCT values (which as promised, you failed to report back about, again telling). You are now apparently after someone writing something agreeing with reports that some people see flicker or experience eye strain or headaches when working with LED backlit monitors. and like your Solux quest, you now aiming at NEC based on your last post. Just tell us what answer you want to hear and someone will hopefully provide it so you will go your own way.
Quote
And since you brought up the issue of "that piece" again, I apparently need to refresh your selective memory: I told you then that I would not respond to your ad hominem attacks and nothing has changed.
I wasn't the only one that asked you to comment about the article that blasted holes in your theories about display calibration. That you havenít commented to anyone and would rather refrain from admitting the article shows your severe misunderstanding of the issue, it is no wonder you would blame your lack of a response on me. The truth is, you don't have the honesty to read what an actual color scientist wrote that points out the flaws in your understanding of color and dismisses the article on the subject YOU yourself posted for comment on PhotoNet. Again, telling.

What's your agenda Frans? You started a post, filled with a lot of nonsense about Solux CCT values. You started another concerning differing products reporting differing values of CCT from the same xyY values and in both cases, the correct replies you got, you didn't accept. You did this on two sites and got the same answers. You are back now apparently looking for problems with some, all or a specific NEC display of which whatever answer you get, it will not be accepted. What stops you from purchasing this NEC, testing it and either keeping it or returning it if you suffer from your head exploding? There's a Linkedin forum for NEC users, why not ask there?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 02:48:36 pm
And since you brought up the issue of "that piece" again, let me refresh your memory: I said at the time that I would not respond to your personal attacks and nothing has changes since then.
There's a significant difference between not being able to respond to an article and not willing to respond. You are unable to respond as the author of the piece submitted to the CIE has far more credibility, an understanding of the subject, and a scientific approach and the article can and does withstand peer review. Your's does not. You are unable to respond because the article uses science and facts to poke holes in your article that used neither.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:06:17 pm
Here are some of the sources (there are many more but you would need to expand the effort to find them):
http://www.tftcentral.co.uk/reviews/nec_p232w.htm
http://www.tftcentral.co.uk/articles/pulse_width_modulation.htm
http://www.mondoarc.com/technology/LED/1079132/led_flicker_safety_issues.html
http://www.lrc.rpi.edu/programs/solidstate/assist/flicker.asp
http://grouper.ieee.org/groups/1789/FlickerTR1_2_26_10.pdf

"get a demo at a good VAR before you put down your money": OK, Andrew, tell me where in the greater Portland, OR area I can find a VAR that can demo me the various high-end NEC monitors, or any high-end monitors for that matter.

"And you didn't specifically ask about this NEC in your original post, you asked about LCD's in general (that's telling). ": I DID ask specifically about the NEC P232W in a previous post, but since I didn't get much reaction, I widened the question to all LED monitors in the hope of getting some useful feedback, if that's OK with you; by the way, YOUR responses haven't been particularly helpful, have they?

"What's your agenda Frans?: My "agenda" is to learn about LED backlit monitors in general and, if there is anybody using the P232W, about that monitor in particular. What's your agenda, Andrew? Oh, never mind. It's pretty obvious.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:09:34 pm
"There's a significant difference between not being able to respond to an article and not willing to respond.": I'll only repeat this one more time - I told you then and I tell you now that I won't respond to that series of personal attacks. Go read what you wrote then and tell me if YOU would respond if somebody used that kind of language. Have a nice day.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 03:21:48 pm
"There's a significant difference between not being able to respond to an article and not willing to respond.": I'll only repeat this one more time - I told you then and I tell you now that I won't respond to that series of personal attacks.
Sorry if the concept of peer review, a process that pokes holes in your concepts seems like an attack. Keep in mind you brought up the subject! This is the result of your original post on PhotoNet you started introducing readers to your new article on the Solux site that's incorrect in a number of areas. The CIE article simply points out the folly of your assumptions. The article I reference has zero personal attacks. It does dismiss your piece. You know it, I know it. You can't defend it. End of story.

The quest to find how, if, and when some backlit LCD will produce migraines,epilepsy etc is, as told to you on both forums, based on the display and or course the end user. No matter what anyone tells you, the quest only fulfills itself when you purchase or demo said display and suffer migraines,epilepsy etc. The rest is just a quest filled with verbal diarrhea and serves no purpose. Find a VAR, look at whatever display you think you'll purchase and if it produces a migraines,epilepsy etc, you probably shouldn't buy it. How's that for sound advise?

Quote
by the way, YOUR responses haven't been particularly helpful, have they?
Only in again, you can never accept an answer that you don't want to hear. I told you I have NO issues with the LED backlit displays I have. Maybe if I told you I suffered migraines,epilepsy etc, you'd have enjoyed the post a tad more.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 03:26:11 pm
OK, Andrew, tell me where in the greater Portland, OR area I can find a VAR that can demo me the various high-end NEC monitors, or any high-end monitors for that matter.

Pro Photo Supply
1112 NW 19th Avenue
Portland, OR 97209
800-835-3314

I did a CMS seminar June 2012, good company. Ask for Jon Combs.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:30:12 pm
"The article I reference has zero personal attacks." Oh, come on, Andrew. It is YOUR personal attacks, and THAT's the end of the story.

I'm so glad to hear that you have no issues with your monitor. Any comments on the articles I referred to or are those people just as uninformed as I am? Have a nice day.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:38:08 pm
"Pro Photo Supply...good company." Oh, that company! You mean the one that doesn't sell NEC? You mean the one that sold me a Hurricane blower that blew tiny rubber particles onto my DSLR's sensor that wouldn't come off, so it had to be returned to Nikon for repairs and then let Nikon pay for it? The company that kept selling the Hurricane blower while they were aware of what it did? You really mean that company? Yeah, I have a lot of confidence in them!
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 03:39:35 pm
Any comments on the articles I referred to or are those people just as uninformed as I am?
Yes, some people, a tiny group may suffer migraines,epilepsy etc, are you in that category? IF so, then don't you think you'd want to:
1. Avoid any or all LED backlit displays?
2. Test any you might buy?
3. Dismiss anything anyone else reports because they probably do not suffer these effects which your articles point out are affecting a tiny amount of users?
Or like your post on PhotoNet, it's the grassy knoll conspiracy issues of NEC, producing on purpose a display that would produce these effects, then forcing those people to spend more on a display? You wrote:
Quote
I'm interested in this issue because I plan to buy an LED backlit monitor, not because I have one already. I've asked NEC why one monitor has a pulse width modulation frequency of 180Hz (anything below 500Hz or even 1kHz may cause issues for some people) and the other two have 8kHz and 20kHz. As en electrical engineer I believe it would be easy to increase the frequency of the 180Hz one to something well above 1kHz. I hate to think that NEC would use 180Hz for the lower cost, 23" monitor on purpose, so they could sell up if people have issues with it, but you never know. I'm waiting for NEC to respond; their chat and next higher level support people didn't even understand the term pulse width modulation frequency, as far as I could tell, and my questions have been bumped up to engineering in Chicago and/or Japan.
You are waiting on NEC, much like you are waiting on Solux which apparently smartly ignores you. And IF NEC told you there's no such issue, as a sufferer of migraines,epilepsy etc, you'd buy the display without the ability to take it back? Again, what's really your quest here Frans? There is no issue. The display is either going to cause you migraines,epilepsy etc and you should be smart enough before you buy, or it isn't. No matter how many people tell you what you've heard here (some have no issues, some see issues), what's the point? You yourself will have to sit down in front of whatever you buy and see if you suffer migraines,epilepsy etc. IF and WHEN that happens, we're all ears. Until then, what exactly do you want us to tell you?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 03:40:37 pm
Oh, that company! You mean the one that doesn't sell NEC?

You asked:
Quote
or any high-end monitors for that matter.
Eizo fits into that category quite well.

Here's a company that will supply the display you're looking at and IF you don't like it, will gladly refund your money upon return:
http://www.amazon.com/NEC-Display-P232W-BK-23-Inch-LED-Lit/dp/B008ABO7WI/ref=sr_1_1?ie=UTF8&qid=1379965340&sr=8-1&keywords=NEC+P232W
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:49:45 pm
"You are waiting on NEC, much like you are waiting on Solux which apparently smartly ignores you." It just so happens that SoLux has acknowledged that they have a problem. Stay tuned. And NEC apparently has a problem to formulate a response to my simple question in a timely manner: why is the PWM frequency of the P232W so low and are you planning to change it?

Yes, you are right: Eizo is high end, but I won't buy their products. And thank you so much for pointing out that I could buy on the internet with a solid return policy. Gee, I never even thought of B&H (where I buy most of my photography related items anyway). Should I refresh your memory and tell you again that I am trying to learn about LED backlit monitors before I jump?

Any feedback on the articles I referred to?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 03:54:57 pm
Any feedback on the articles I referred to?

I told you my feedback. Let me add to those that might consider suggesting you do anything other than view such displays IF you're so worried about migraines,epilepsy etc:

(http://digitaldog.net/files/trolls.jpg)

Quote
Stay tuned.
Yes, you've said that many times. My reply was and continues to be, I'm not holding my breath.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 03:58:44 pm
"I'm not holding my breath." I'm glad to hear that. Should I also start posting insulting images? Ah, no.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 04:06:34 pm
It just so happens that SoLux has acknowledged that they have a problem.
I told you and illustrated that months ago (June)! Along with Robin Myers and Tim Vitale when we showed you three proper measured processes you refused to accept. You were so sure your facts and faulty measurements were right when of course, they were not. Just like several of us told you here and on PhotoNet that Three different color calculators CAN be wrong (different), which again you dismissed and argued about. Don't give any of us credit for attempting to steer you into the right direction. Same with this post. IF you really believe you have an issue with migraines,epilepsy etc, there is no solution other than sitting in front of the questionable display and seeing if it affects you. What Solux or NEC tells you isn't pertinent.

For that matter, anyone serious about purchasing a display (or a TV) probably should look at one before they buy.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 04:11:49 pm
Let's stick to the issue at hand: LED backlit displays. Anything else you want to contribute on this issue?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on September 23, 2013, 04:16:03 pm
Let's stick to the issue at hand: LED backlit displays. Anything else you want to contribute on this issue?
No, I'm done here.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Manoli on September 23, 2013, 04:52:30 pm
Yes, you are right: Eizo is high end, but I won't buy their products.

And, why not ?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 23, 2013, 06:49:35 pm
I won't buy Eizo, because the experts, like Andrew Rodney, tell me NEC is just as good or better than Eizo at a much more affordable price.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: John.Murray on September 23, 2013, 11:59:08 pm
I feel for BC, as my sister also suffered from a detached retina.  She is very sensitive to any flicker and is equally sensitive to florescent and led backlights.....

In my experience (anecdotal - but covering thousands of users) some select individuals are sensitive - the overwhelming majority are *not*.

Macs with external displays, along with all Windows machines have the ability to adjust the vertical refresh, curiously Macbooks and Imacs do not have this available (why?) - often this can help to reduce the effect, but again with some rare individuals, nothing really helps.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: mlewis on September 24, 2013, 05:00:00 am
Macs with external displays, along with all Windows machines have the ability to adjust the vertical refresh, curiously Macbooks and Imacs do not have this available (why?) - often this can help to reduce the effect, but again with some rare individuals, nothing really helps.
Changing the vertical refresh of LCD displays won't change any flickering.  With CRT displays the opposite is true.  Any flickering with LCD displays is purely down to the backlight.  Most LCD monitors only work with a 60Hz vertical refresh anyway.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on September 25, 2013, 11:25:50 pm
Today, NEC confirmed that they are aware of the potential problems of flicker, eye strain, headaches, etc. caused by the low pulse width modulation frequency (just 180Hz) of the W-LED backlighting of their 23" P232W LCD monitor. They also said there are no plans to increase this frequency, which in my opinion would be very easy to do; similar W-LED backlighting of the 24" P242W runs at over 8,000Hz and is as such problem-free. They advice to buy the P242W, which is US$200 more expensive, if you have issues with flicker, eye strain, headaches, etc. If you consider the P232W, better evaluate before you buy or buy with a solid money-back warranty, which is what I am going to do.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 10, 2013, 02:18:32 am
B&H has been my prefered store for many years and I haven't had a single issue with them. So I was a little disappointed when they told me that if the low 180Hz frequency backlighting pulse width modulation (PWM) of the NEC P232W-BK-SV would cause issues for me, they would not pay for return shipment. Their rationale is that the monitor is supposed to work at that frequency and as such is not defective and I can't disagree with that. They are right, but not as flexible as I would have liked. B&H has definitely become more rigid in their attitude; a couple of years ago they would replace at their expense any monitor that I would find personally unacceptable for backlight bleeding, something that is not even specified. Oh well, the times they are achanging. So I decided to not even bother and bought the next higher up model, the P242W-BK-SV (with 8,000Hz PWM) from B&H. Great monitor. Calibration is easy and at 4900K and 105 nits I get a great match with my prints illuminated by the 4900K SoLux bulbs.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Pics2 on October 10, 2013, 04:31:45 am
B&H has been my prefered store for many years and I haven't had a single issue with them. So I was a little disappointed when they told me that if the low 180Hz frequency backlighting pulse width modulation (PWM) of the NEC P232W-BK-SV would cause issues for me, they would not pay for return shipment. Their rationale is that the monitor is supposed to work at that frequency and as such is not defective and I can't disagree with that. They are right, but not as flexible as I would have liked. B&H has definitely become more rigid in their attitude; a couple of years ago they would replace at their expense any monitor that I would find personally unacceptable for backlight bleeding, something that is not even specified. Oh well, the times they are achanging. So I decided to not even bother and bought the next higher up model, the P242W-BK-SV (with 8,000Hz PWM) from B&H. Great monitor. Calibration is easy and at 4900K and 105 nits I get a great match with my prints illuminated by the 4900K SoLux bulbs.
I just ran across this thread. I wasn't aware of the problem, but it sounds logical. Since I plan to buy NEC PA 271W, and since I can't find PWM specification for this monitor, do you know how good is this monitor, is it free of the problem? Thanks!
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 10, 2013, 10:48:06 am
I just ran across this thread. I wasn't aware of the problem, but it sounds logical. Since I plan to buy NEC PA 271W, and since I can't find PWM specification for this monitor, do you know how good is this monitor, is it free of the problem? Thanks!
It's pretty much a made up problem (a problem for a tiny few) and further, the PA271W is just fine, isn't an LED backlight.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 10, 2013, 12:59:55 pm
"It's pretty much a made up problem (a problem for a tiny few)" Really, Andrew? In the U.S. alone 100,000 or more people may affected from seeing flicker or having headaches all the way to epilepsy.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 10, 2013, 01:03:53 pm
"It's pretty much a made up problem (a problem for a tiny few)" Really, Andrew? In the U.S. alone 100,000 or more people may affected from seeing flicker or having headaches all the way to epilepsy.
Considering the total population of the US, assuming your figure are correct (not something you're prone to provide) and considering how many are purchasing LED backlit LCD displays, yes it's a tiny issue for few.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 10, 2013, 03:11:34 pm
Andrew, instead of declaring it a non-issue without having the facts, you might want to do a little research yourself. The number of 100,000 people is in my opinion a conservative estimate because it is based on old studies about severe cases only. And then there is the factor that LED backlit monitors are becoming more and more prevalent and with it the potential for people to run into issues, where in the past they didn't have issues because the afterglow of CCFL backlighting greatly reduces the flicker effects.

Given the potential for problems and the relative easy fix for the P232W I still don't understand why NEC doesn't plan to upgrade that monitor with a much higher backlighting PWM.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 10, 2013, 03:38:08 pm
Andrew, instead of declaring it a non-issue without having the facts, you might want to do a little research yourself. The number of 100,000 people is in my opinion a conservative estimate because it is based on old studies about severe cases only.
I'm only returning to this silly post to answer Pics2's question about 'this (non) issue' and the PA271W. But to followup on your statement, it's only apparently a issue to you, at least around these parts! Look, 4-5% of the 319 million US population suffer from Peanut allergies*. That comes to 15,700,000 people! A tad more than 100,000 who 'suffer' from fatigue from display flickering. I'd submit that a fraction (if any) of these 15,700,000 people go out and purchase let alone then eat Snicker bars! They have a clue there's an issue. They avoid peanuts. Assuming the far smaller group of 100,000 people have issues with display flicker, all they have to do is avoid the displays as I advised you to do (if indeed you are one of the 100,000 in the group, you of course have never admitted this was an real issue). Even if the number is 200,000, how many are buying LED LCD displays? Like the web is filled with complaints on forums from people who suffer issues with LED displays? Can't you find something more salient to post in photo-centric forums than this minutia?

Presumably anyone with a half a brain who suffer from any issue will avoid what ails them. IF (huge if) you or anyone out to purchase a display have flicker issues, take the unit back or don't buy one in the first place. Big Friggin deal. WHY you have to make this a federal case and a major issue on two differing forums is what I'd like to know. I told you on PhotoNet if you don't like the spec's of the entry level NEC, get the next model up which you ended up doing. You followed common sense advise which is comforting.

*http://www.niaid.nih.gov/topics/foodAllergy/understanding/Pages/quickFacts.aspx
Quote
Given the potential for problems and the relative easy fix for the P232W I still don't understand why NEC doesn't plan to upgrade that monitor with a much higher backlighting PWM.
Of course you don't. You have to make this some silly conspiracy theory 'issue' target at NEC. They don't hide the spec's anymore than Snicker's hides the fact's it is filled with peanuts and any consumer who has an issue with that ingredient can avoid purchasing it. And unless you were a fly on the wall at NEC when this entry level display was first designed you have absolutely no idea that this is an easy fix nor why they built it as they did. Further, a fix implies something is broken and if you do some simple math and take twice the number of people you claim have flicker issues and look at the percentage of the population of the US, then those who might purchase an NEC, you see it's a tiny and insignificant number of people. Now recognize that NEC sells displays worldwide, take that population and your idea this is a problem becomes even more comical. There's nothing to fix because based on how the product was designed, there's nothing broken. Just as Snicker bar's are not broken because they have peanuts and at least a decent number of people are allergic to them.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Pics2 on October 10, 2013, 05:09:46 pm
Thank you for you reply Andrew! I'm sorry if I got you in trouble  :D
This is an interesting debate, thank you both.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 10, 2013, 11:51:13 pm
OK, Andrew, you are onto something, but I doubt if you realize it! You said: "Now recognize that NEC sells displays worldwide, take that population and your idea this is a problem becomes even more comical." Remember that the 100,000 or so are just in the US, not worldwide. So, worldwide there are potentially 2 million people with severe sensitivity to flicker. Yeah, Andrew, that's a non-issue!

And then you say: "And unless you were a fly on the wall at NEC when this entry level display was first designed you have absolutely no idea that this is an easy fix nor why they built it as they did." Well, I do have some ideas and let me explain. The backlighting of the P232W and P242W are both W-LED and if NEC can pulse the larger-area, higher-power W-LED system of the P242W at more than 8,000Hz, they ought to be able to use the same frequency for the smaller-area, lower-power W-LED system of the P232W, but instead they use 180Hz, a frequency NEC admits can cause problems. And then there is the fact that as an electrical engineer with many years of experience with all kinds of optoelectronics I know that LEDs are easy to switch on and off at frequencies way higher than 8,000Hz.

And I have an idea why the P242W is the way it is: it's a LED upgrade of the previous CCFL version, everything else is pretty much the same, and NEC apparently didn't think it important enough to use a higher frequency PWM to avoid any potential issues.

Your comparison with peanut allergies doesn't hold any water. If you have peanut allergies you just can't eat products containing peanuts. If you have flicker issues, you don't have to suffer at all if the monitor companies were aware and increased the PWM frequency. And were are not talking about NEC only; there are plenty of other monitor brands with low PWM frequencies.

Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 11, 2013, 09:44:52 am
Yeah, Andrew, that's a non-issue!
It sure isn't if you are as intelligent as the now worldwide base of people allergic to peanuts and don't buy then eat a snickers bar.
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I know that LEDs are easy to switch on and off at frequencies way higher than 8,000Hz.
Sure you do, that's why you're currently an engineer at NEC. You have no idea of the costs and as I pointed out, the display was designed the way it was for a reason just as Snickers bars were designed with peanuts despite the worldwide populateion who can't eat them.
This is a non issue for anyone who has a clue about a potential (and in this context rare) condition. As I said, only you seem to be populating photocentric cites with this so called problem with flicker. The rest of us are happy making images or finding other more worthy pursuits, you should give it a try sometime.
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And I have an idea why the P242W is the way it is: it's a LED upgrade of the previous CCFL version, everything else is pretty much the same, and NEC apparently didn't think it important enough to use a higher frequency PWM to avoid any potential issues.
They were correct. It isn't important.
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Your comparison with peanut allergies doesn't hold any water. If you have peanut allergies you just can't eat products containing peanuts. If you have flicker issues, you don't have to suffer at all if the monitor companies were aware and increased the PWM frequency.
Sure it washes, if you have issues with flicker, don't buy a display that flickers that you can see. Considering the tiny numbers we're talking about, again, a non issue expect for you who one has to wonder even has an issue with flicker.  Anyway, I'm done, I answered Pics2's question and hopefully he can sleep at night not worrying about this ridiculous issue you continue to post about. You should spend more time worrying about our food quality with the governmental shutdown than this sillyness.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Farmer on October 13, 2013, 06:48:03 pm
2,000,000 world wide would be 0.03% of the world's population.  It also assumes that all those 2,000,000 use LCD monitors (clearly not true) and specifically LED backlit LCD monitors and specifically those with a noticable flicker for them.

The degree of the effect on those people would also vary, with only a fraction of them significantly affected.

So the total potential exposure is tiny.

As Andrew suggests, those who suffer from it will likely know or soon discover and can avoid such purchases.  The onus should not be on NEC (or anyone else) to change their product for such a small proportion.  If enough people don't like it, they'll stop buying and NEC (or anyone else) will then react accordingly.

Basically, take responsibility for yourself and don't rely on others.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 13, 2013, 11:35:20 pm
those who suffer from it will likely know or soon discover and can avoid such purchases.
I don't quite get your logic. How can you avoid such purchases if you don't know you have such sensitivity? Answer: you can't. Many people that have the sensitivity don't even know that it is caused by the flicker of the monitor or fluorescent or LED lamps. NEC acknowledged they are aware of the issue with the P232W, but say they won't correct it, something that should be very easy to do by changing one or two component values or, even easier to do, change the timing through firmware. And NEC knows very well how to do that; the exact same backlighting in the P242W works at a way higher frequency (8,000Hz versus 180Hz). So, chalk this one up to sloppiness or a the-devil-may-care attitude, your choice.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 14, 2013, 07:45:27 pm
You should spend more time worrying about our food quality with the governmental shutdown than this sillyness.

Oh, you mean the government that allows 7.5% of chickens for human consumption to be contaminated with salmonella? That government?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 14, 2013, 08:11:46 pm
Oh, you mean the government that allows 7.5% of chickens for human consumption to be contaminated with salmonella? That government?
You are as misguided and worried about chicken with salmonella as you are about displays with flicker. It's a non issue expect for stupid people who eat raw chicken! Cook it to 165+ degrees, no more salmonella. And even if you're as concerned about salmonella as display flicker (you shouldn't be concerned with either), with the FDA/FSIS shutdown, you can keep yourself up at night worrying about far more than 7.5% of chickens for human consumption to be contaminated with salmonella assuming you're dumb enough to be eating that percentage of chicken raw. Bottom line, if you're really that concerned about 7.5% of chickens for human consumption to be contaminated with salmonella, thank the nuts in the house who were responsible for shutting down the government!

Maybe that Government needs to tackle that awful issue of display flicker, that your idea Frans?
http://usnews.nbcnews.com/_news/2013/10/08/20873175-routine-fda-inspections-of-food-facilities-suspended-due-to-government-shutdown#comments
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 15, 2013, 12:39:50 pm
You just don't get it, do you, Andrew? I'm not a food safety expert (are you?), but for the sake of argument let's assume that your assertion that salmonella on chickens for human consumption is no safety issue. So, why then the 7.5% regulation? It's either safe (as you assert) or it isn't. You either need no regulation or you need a way, way stricter one, like zero-tolerance. And who came up with the 7.5%? Not 7, not 8, but 7.5%? And, as a side note, very revealing, your remark about "the nuts in the house".

And who is making all the fuzz here about monitor flicker? It's you, Andrew. You can't stop attacking me over it. It's an issue for some people and so your assertion that it is a non-issue is incorrect. People should be aware of it and increasingly are becoming aware of it, in part "thanks" to more LED monitors being sold, many of them with too low a pulse width modulation frequency. And yes, I wanted to know as much as possible about it before I plunked down a wad of money on a new monitor. Is that OK with you?
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 16, 2013, 10:46:18 am
I believe the OP may suffer from Cyberchondria  :D:
http://www.techhive.com/article/2054386/eight-new-mental-illnesses-brought-to-you-by-wait-for-it-the-internet-.html#tk.rss_all
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: Frans Waterlander on October 16, 2013, 12:43:53 pm
You are making my point exactly: "And who is making all the fuzz here about monitor flicker? It's you, Andrew." Give it a rest.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: bcooter on October 16, 2013, 02:22:17 pm
I believe the OP may suffer from Cyberchondria 

Andrew, don't be a d__k.

Yes I think a lot of internet buzz is just that buzz, but until you really have an issue, like a detached retina and you work for two hours and it hurts, you'd have a much different view on this.

My eye issue is mine alone and I don't expect Apple or NEC to build a monitor just for me, but I do wish I would have known what the new monitors would do before I bought two of them, which are non returnable.

I work around it, eat Advil, meet deadlines and go on with my life, but it's amazing I can set down and work 14 hours virtually straight on a 30" dell and it's just a no thought process.  The new backlit Apple monitors are hell, but that's not a whine or complaint, it's just a fact.

I'm curious do you park in handicap zones because you feel people in wheelchairs are just faking it?

IMO

BC


Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 16, 2013, 02:26:11 pm
My eye issue is mine alone and I don't expect Apple or NEC to build a monitor just for me, but I do wish I would have known what the new monitors would do before I bought two of them, which are non returnable.
How'd you manage that? It IS possible to purchase a display (or many other products) and return them. At least within a reasonable time frame to test the products.
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I'm curious do you park in handicap zones because you feel people in wheelchairs are just faking it?
Nope but I do my best when finding people who park there when they shouldn't end up handicapped.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: digitaldog on October 16, 2013, 02:36:06 pm
 bcooter, let me say I do feel for you due to your condition. I can understand how this could be a serious and painful ailment. With that said, I'd think anyone in your shoes would and should be super careful about selecting a display or for that matter, anything that relies on your vision to conduct work. As I suggested early on to Frans, IF he's so sure he suffers issues with backlit LED displays (and there's zero evidence of this), he find a source that will provide a demo or a means of returning the product should it not work out. To suggest NEC or any other company is deliberate in producing a product it's customers would suffer from is just silly and no one forces these products onto people who know they may have an issue.
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: bcooter on October 16, 2013, 02:56:56 pm
bcooter, let me say I do feel for you due to your condition. I can understand how this could be a serious and painful ailment. With that said, I'd think anyone in your shoes would and should be super careful about selecting a display or for that matter, anything that relies on your vision to conduct work. As I suggested early on to Frans, IF he's so sure he suffers issues with backlit LED displays (and there's zero evidence of this), he find a source that will provide a demo or a means of returning the product should it not work out. To suggest NEC or any other company is deliberate in producing a product it's customers would suffer from is just silly and no one forces these products onto people who know they may have an issue.

Like a lot of people, I work huge hours, in today's new economy and have very little time. 

That's fine, no complaints and actually I have no complaints about the Apple monitors because as I've said they can't test for everyone.

But I don't and didn't have time to look for a problem I've never had.  My eye is problematic, I'm use to it, but I've never had a monitor do what the new ones do, so I didn't expect the issue.

Then again when I bought the new Imac it was just a stop gap until the new Apple desktop comes out, but never in my wildest dreams did I think that in two hours I'd have to get up and walk around the patio to clear my head and right now, since so much of our work is motion and I still use FCP 7 (me and about 75% of the market) the new Imac is the only computer that will fly with the legacy fcp.

But your right, this falls on me, not Apple, though I wish the desktop was out because I'd have gone that direction and added my 30" dells because I know how well they work for me.



IMO

BC

Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: ZoeSanderson on July 06, 2020, 01:28:20 pm
I don't quite get your logic. How can you avoid such purchases if you don't know you have such sensitivity? Answer: you can't. Many people that have the sensitivity don't even know that it is caused by the flicker of the monitor or fluorescent or LED lamps. NEC acknowledged they are aware of the issue with the P232W, but say they won't correct it, something that should be very easy to do by changing one or two component values or, even easier to do, change the timing through firmware. And NEC knows very well how to do that; the exact same backlighting in the P242W works at a way higher frequency (8,000Hz versus 180Hz). So, chalk this one up to sloppiness or a the-devil-may-care attitude, your choice.
My friend was just looking for this information. Thanks
Title: Re: Flicker, eyestrain or headache when using a monitor with LED backlighting?
Post by: ZoeSanderson on July 06, 2020, 01:30:51 pm
Like a lot of people, I work huge hours, in today's new economy and have very little time. 

That's fine, no complaints and actually I have no complaints about the Apple monitors because as I've said they can't test for everyone.

But I don't and didn't have time to look for a problem I've never had.  My eye is problematic, I'm use to it, but I've never had a monitor do what the new ones do, so I didn't expect the issue.

Then again when I bought the new Imac it was just a stop gap until the new Apple desktop comes out, but never in my wildest dreams did I think that in two hours I'd have to get up and walk around the patio to clear my head and right now, since so much of our work is motion and I still use FCP 7 (me and about 75% of the market) the new Imac is the only computer that will fly with the legacy fcp.

But your right, this falls on me, not Apple, though I wish the desktop was out because I'd have gone that direction and added my 30" dells because I know how well they work for me.



IMO

BC
Why didnít anyone tell me about this some months ago?!