Monitor response time is a factor for me
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Seagull yeah sorry that's my bad, I've edited the original post. Slower response time is better for me.
I am the worst at proof reading!
So if slow response time is good have you tried a mainstream IPS panel like in a laptop? Those are usually mid 20s so if slowing it down actually helps then those should be even better. I know for me at least this is irrelevant since IPS panels with slow response times hurt as much as a 5ms TN panel. I would bet this is something else..like one of those displays has internal software that dithers or something, than the response time of such a small difference making it good vs bad.
*Not trying to ruin your mood...its just we need replication and logical comparison to multiple displays with other response times to even assume this is related.
Al ips monitors give me migraines so its a no go for me unfortunately- though I think that's unrelated to my general issues with dithering. I don't yet know why ips panels give me migraines, but I am finding more evidence that its the horizontally polarised light they emit that triggers them. In contrast, tn lcd panels emit light at 45degrees. I am actually in the process of making some polarised glasses to test if horizontally polarised light is the reason ips panels give me migraines - but as I say, I am pretty sure the migraines are unrelated to the eye strain I get from dithering.
In response to your earlier post, you are right, 3ms doesn't sound like much, but as a percentage its a bit more impactful. The faster screen spends 12% of its time between frame changing the pixels and 88% displaying a static image. The slower screen spends 30% of its time changing the pixels and 70% displaying a static image. I think that slower change might be a bit like how pwm on a ccfl is more tolerable than on a led blacklight - because there is more of a gradual on-off rather than a sudden change.
Happy to concede that it could be something else, but this is the best explanation that I can quantify.
I also have a VA monitor that I am waiting to try, as they have slower response times - though I won't try it till I have finished my polarised light migraine experiments.
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@Seagull Not all IPS displays put out horizontally polarized light. It varies between brands and even models in a brand. In fact most put out VERTICALLY polarized light (you sound like you know this...but you can tell by wearing polarized sunglasses since they are meant to filter out horizontal sheets of light glaring from the ground/water, and if you can still see the display its vertically polarized because that's all they allow in...if you cannot its horizontally polarized but if you turn them 90deg then you could see. All LG panels I have tried use horizontal but the rest vary.
I hope this is reproducable and leads to something...but I am dubious that such a small difference could matter...and framing it as percentage doesn't make me believe more since the times we are talking about are SO small I don't think we can notice that. CCFL displays are likely better because its a smooth sine wave rather than an on off harshness...not the speed of the transition. This is largely opinion though so I'd be happy to be proven wrong.
I was not aware that IPS panels can also be vertically polarised, though in my experiments so far I have found that vertical polarisation affects me also but to a lesser extent. it seems that only 45degree polarisation is tolerable for me. I am making some glasses out of polarised camera lens that I will be able to rotate to discover just which angles of polarisation I can tolerate. Until then I can't really be sure how polarisation affects me.
3ms is small, but if you believe ditthering is an issue, then 16ms must be sufficient to cause symptoms, as a 60hz monitor refreshes every 16ms. If dithering is happening then each pixel is changing every 16ms. Is 3ms that much less than 16ms? Then one can consider how the forum member JasonPicard found relief with higher refresh rate monitors - a 144hz monitor will refresh once every 7ms. It seems to me like we are able to perceive differences on the millisecond level.
Obviously my experience only really applies to my specific issues, but honestly I do not think you will find two more similar monitors yet with different response times than the BL221 and the BL2405.
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Seagull Then one can consider how the forum member JasonPicard found relief with higher refresh rate monitors - a 144hz monitor will refresh once every 7ms. It seems to me like we are able to perceive differences on the millisecond level.
This is the sort of dubious conclusion/correlation that makes bad science though. I realize trial and error is all we have for right now, but people are always saying "X proves Y" over and over for things, and it doesn't. There are way more factors involved. I think everyone here has experimented enough to know intuition and one off examples aren't generally solid.
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hpst I have relief even if it's at 60 hz. I attribute that to the fantastic overdrive. I play it all the time with my consoles. Over drive, BFI and a fast TN panel are all you can do right now to get more out of 60hz unless you switch to Plasma/CRT. Then you get 1000hz refresh rate out of 60hz. I would say BFI on 60 is probably not for many people on this forum because it makes things pretty flickery. I have tried it on the Benq 2411P which is one of the few that can do that at such a low refresh rate.
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I wasn't commenting on refresh rate...rather the response time differences of single digits mattering enough to result such a big change in tolerance...and the fact that most laptop panels out there are slow refresh rates and those hurt most people here. I don't have an opinion on refresh rate yet as I haven't experienced high end rates yet to see how they feel to me.
hpst ****https://www.blurbusters.com/gtg-versus-mprt-frequently-asked-questions-about-display-pixel-response/ Here is an awesome article on the difference between MPRT vs GTG. One thing I have noticed for me personally TN has always been better for me even if it was causing pain. IPS was immediate pain all the time and I tried quite a few. I remember trying a few IPS panels because I thought my issues were dithering at one point. Dithering is supposed to be the least pronounced on an IPS panel. I even tried a samsung PLS (Samsungs answer to IPS). I am interested in the new LG IPS that comes out because it's the worlds first IPS that is as fast as a TN. It's not out yet though.
@Seagull do you have further thoughts on this?
I'm really intrigued by this concept. For some reason, I can use most laptops (as long as they don't have PWM) but external monitors almost always cause me problems (even when they don't have PWM). I am currently using a monitor from approximately 2011.
Here's a waveform from LaptopMedia from a laptop that I can use all day long without issues. It has a very slow 31.9 ms response time.
I may play around with my oscilloscope next week.
I don't think my core argument has changed any over the years, I still use the same slower monitors and generally find them comfortable. Some of the details of the original post have changed though. I now know that intel integrated graphics does not use temporal dithering, but my Nvidia card did.
I am wondering how response time interacts with LCD inversion though, perhaps slower responding LCDs smooths out the flickering effect from LCD inversion.
I wanted to find out if the screens that work well for me have faster or slower response times than the ones I cannot use.
Results: It seems plausible to me that a fast rise time (from black to white) causes my symptoms (headache, nausea, tinnitus). Also, very bright screens might exacerbate this issue, since these screens would have a larger total change in brightness from black to white.
The fall time (from white to black) was very similar on my least favorite monitor and my favorite monitor. It seems unlikely that fall time by itself causes my symptoms.
The experiment:
To run the experiment, I created a web page that sets the background to white, waits 40 ms, sets the background to black, waits another 40 ms, and then repeats. I measured the light output of the screen using my oscilloscope and light detector (the one described elsewhere on this forum). I measured seven screens (phones, laptops and monitors) that I like but only one that I absolutely hate ('cause I usually get rid of the ones that I hate).
The monitor I hate (HP LA2405x) had the fastest rise time, fastest fall time, and largest overall change in brightness. I tested this monitor at full backlight brightness (otherwise it has PWM).
My favorite monitor (ASUS VW228TLB-P) was actually the most similar to the monitor that I hate, but the rise time was significantly slower and the overall change in brightness was lower. I also tested this at full backlight/full brightness because that's how I use it on a daily basis.
I've attached the waveforms so you can see the difference.
