Ad
Ad
Ad
Pages: « 1 [2] 3 »   Bottom of Page
Print
Author Topic: Flicker, eyestrain or headache when using a monitor with LED backlighting?  (Read 8097 times)
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #20 on: September 23, 2013, 02:58:44 PM »
ReplyReply

"I'm not holding my breath." I'm glad to hear that. Should I also start posting insulting images? Ah, no.
Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #21 on: September 23, 2013, 03:06:34 PM »
ReplyReply

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.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #22 on: September 23, 2013, 03:11:49 PM »
ReplyReply

Let's stick to the issue at hand: LED backlit displays. Anything else you want to contribute on this issue?
Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #23 on: September 23, 2013, 03:16:03 PM »
ReplyReply

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.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Manoli
Sr. Member
****
Offline Offline

Posts: 429


« Reply #24 on: September 23, 2013, 03:52:30 PM »
ReplyReply

Yes, you are right: Eizo is high end, but I won't buy their products.

And, why not ?
Logged
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #25 on: September 23, 2013, 05:49:35 PM »
ReplyReply

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.
Logged
John.Murray
Sr. Member
****
Offline Offline

Posts: 893



WWW
« Reply #26 on: September 23, 2013, 10:59:08 PM »
ReplyReply

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.
« Last Edit: September 23, 2013, 11:02:42 PM by John.Murray » Logged

mlewis
Newbie
*
Offline Offline

Posts: 25


« Reply #27 on: September 24, 2013, 04:00:00 AM »
ReplyReply

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.
Logged
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #28 on: September 25, 2013, 10:25:50 PM »
ReplyReply

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.
Logged
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #29 on: October 10, 2013, 01:18:32 AM »
ReplyReply

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.
Logged
Pics2
Full Member
***
Offline Offline

Posts: 150


« Reply #30 on: October 10, 2013, 03:31:45 AM »
ReplyReply

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!
Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #31 on: October 10, 2013, 09:48:06 AM »
ReplyReply

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.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #32 on: October 10, 2013, 11:59:55 AM »
ReplyReply

"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.
Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #33 on: October 10, 2013, 12:03:53 PM »
ReplyReply

"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.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #34 on: October 10, 2013, 02:11:34 PM »
ReplyReply

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.
Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #35 on: October 10, 2013, 02:38:08 PM »
ReplyReply

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.
« Last Edit: October 10, 2013, 03:03:19 PM by digitaldog » Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Pics2
Full Member
***
Offline Offline

Posts: 150


« Reply #36 on: October 10, 2013, 04:09:46 PM »
ReplyReply

Thank you for you reply Andrew! I'm sorry if I got you in trouble  Cheesy
This is an interesting debate, thank you both.
Logged
Frans Waterlander
Jr. Member
**
Offline Offline

Posts: 58


« Reply #37 on: October 10, 2013, 10:51:13 PM »
ReplyReply

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.

« Last Edit: October 11, 2013, 01:38:37 AM by Frans Waterlander » Logged
digitaldog
Sr. Member
****
Online Online

Posts: 8096



WWW
« Reply #38 on: October 11, 2013, 08:44:52 AM »
ReplyReply

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.
Quote
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.
Quote
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.
Quote
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.
« Last Edit: October 11, 2013, 08:52:58 AM by digitaldog » Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Farmer
Sr. Member
****
Offline Offline

Posts: 1608


WWW
« Reply #39 on: October 13, 2013, 05:48:03 PM »
ReplyReply

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.
Logged

Pages: « 1 [2] 3 »   Top of Page
Print
Jump to:  

Ad
Ad
Ad