Dell S-Line Screens - S2740L, S2440L, S2340M, S2340L, S2240M

IPS glow of the S2240M. White line near center, was for my mediocre point and shoot camera to be able to auto-focus. This is at 15 Brightness 75 Contrast, in a darkened room. So it is slightly exaggerated from normal usage.

With the same image, I attempted to use TFT Centrals PWM method, http://www.tftcentral.co.uk/articles/content/pulse_width_modulation.htm. With only a few stable shots, I could not definitively rule out PWM.

IMG_3783.jpg
 
clonalvex said:
IPS glow of the S2240M. White line near center, was for my mediocre point and shoot camera to be able to auto-focus. This is at 15 Brightness 75 Contrast, in a darkened room. So it is slightly exaggerated from normal usage.

With the same image, I attempted to use TFT Centrals PWM method, http://www.tftcentral.co.uk/articles/content/pulse_width_modulation.htm. With only a few stable shots, I could not definitively rule out PWM.

IMG_3783.jpg
Click to expand...

probably the biggest reason i went with the S2440l , ips glows sucks worse then grey blacks, ips has a problem with light leakage more now than ever ,
 
You need to move the camera sideways while shooting, to get the multiple line effect that comes from PWM.
Its also rather easy to see the flickering if you swing something, like a pen, rapidly and repeatedly infront of a bright background. If you have PWM a stroboscope (or "wagon-wheel') effect will show.
 
ok been using s2440L for two days now. no pwm (100% brightness) on this and no FRC on this either... yet when i move my eyes quickly from one corner to another like looking from file menu to the cross button sometimes or top down or diagonal or when you are reading text somewhere in centre down area and quickly move eyes upto the address bar you see flicker.. i see a flicker/pulsation for half a second or so like you see rainbow pattern in dlp projectors when quickly moving your head in black and white scenes.. i'm not sure where this is coming from. Any ideas?
 
dopple said:
thats why i said it is even in the ips panels. bcause that is what i see in s2440l with contrast down and brightness up.
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on a black screen? i don't have an s2440l to test so i'm just guessing here, but can you see this effect with contrast at its default value rather than turned all the way down? on lcd's you generally don't want to mess with the contrast setting as it changes the digital white level and gamma. this combined with va gamma shift might explain what you are seeing, but this is not the same as ips glow even if it looks similar to you.

best way for us to diagnose this is for you to post a video of the effect.
 
dopple said:
thats why i said it is even in the ips panels. bcause that is what i see in s2440l with contrast down and brightness up.
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scratch my last comment - i read tft central's review of the s2440l and they did mention that it has an off-angle purple glow. this would be exacerbated if you crank the brightness all the way up.
 
livefastdieyoung said:
scratch my last comment - i read tft central's review of the s2440l and they did mention that it has an off-angle purple glow. this would be exacerbated if you crank the brightness all the way up.
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its worse because of amva gamma shift. so you end up with the situation in the video i linked to.

a tn panel is way better specifically in this special situation with 100% brightness and low contrast.
 
Are you really talking about gamma shift or isnt it more 'off center contrast' that is often mentioned together with VA panels? That is you got contrast variations depending on viewing angle? With TN there is a gamma variation with angle, but less contrast variation.
 
CrabJuice said:
You need to move the camera sideways while shooting, to get the multiple line effect that comes from PWM.
Its also rather easy to see the flickering if you swing something, like a pen, rapidly and repeatedly infront of a bright background. If you have PWM a stroboscope (or "wagon-wheel') effect will show.
Click to expand...

Hmm, well that is a bit disappointing. The difference between 100 brightness and any increment below it is strikingly obvious now, while displaying a full white screen. Quickly waving a black felt pen in front of the screen at 100 brightness the movement is completely smooth, as waving it in front of myself under sunlight or even the LED lights I have in my home. At any other setting, the strobe like effect is abhorrently apparent.
 
CrabJuice said:
Are you really talking about gamma shift or isnt it more 'off center contrast' that is often mentioned together with VA panels? That is you got contrast variations depending on viewing angle? With TN there is a gamma variation with angle, but less contrast variation.
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you're right i think it could be the off centre contrast. either way this problem is way worse than tn viewing angles. for tn panel viewing angle issue i have to get up from my chair and move around to see this problem.. with amva i just have to very slightly move my head position left or right sitting where i am.
 
dopple said:
you're right i think it could be the off centre contrast. either way this problem is way worse than tn viewing angles. for tn panel viewing angle issue i have to get up from my chair and move around to see this problem.. with amva i just have to very slightly move my head position left or right sitting where i am.
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I think the off centre contras in AMVA panels can be solved simply by standing further away from the monitor,at least that's what I saw...
 
marikso said:
I think the off centre contras in AMVA panels can be solved simply by standing further away from the monitor,at least that's what I saw...
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when you lower brightness the blacks and contrast are tremendous but then you get PWM flicker. its a tradeoff. If the backlight was better this would have been a very good display.
 
dopple said:
you're right i think it could be the off centre contrast. either way this problem is way worse than tn viewing angles. for tn panel viewing angle issue i have to get up from my chair and move around to see this problem.. with amva i just have to very slightly move my head position left or right sitting where i am.
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Its just my opinion and a matter of view but i have to say in no hell way is the veiwing angles on this like a tn or worse and im super picky to where ips angle bother me with seeing backlight bleed .. and as for the flickering issue also I have had it on the lowest brightness setting and havent seen it in the least ... I would suspect a panel lottery going on .
 
can someone with s2440 connect via hdmi-hdmi and check this website http://www.hairlosstalk.com/ fullscreen it and scroll up and down the site.. does your monitor flicker in the white background of this website on the left and right of the screen?

mine is.. but not via vga.
 
clonalvex said:
Hmm, well that is a bit disappointing. The difference between 100 brightness and any increment below it is strikingly obvious now, while displaying a full white screen. Quickly waving a black felt pen in front of the screen at 100 brightness the movement is completely smooth, as waving it in front of myself under sunlight or even the LED lights I have in my home. At any other setting, the strobe like effect is abhorrently apparent.
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whew!

After seeing how this Test is run, I went to my s2440l to check this, informally. I set the brightness at zero with 100% contrast and then brough up the wordpad program.

a nice white white screen.

i s-l-o-w-l-y, slowly moved my finger back and forth and then sped my movement up a bit.

zero flicker!
none!
????
there *must* be Something Going On!

either this is a "panel lottery" problem, or that there is esoteric combinations of video card + currant cycle local-variations + ????.

the simplest explanation that I can think of is that Dell outsourced some of the panel manufacturing to other factories and one of more of these factories did not make this to Dell specs! too too bad there is not a simple way to check the panel model number. Dell could end up with a fail-to-sell product, from this as probably they did not want to have people checking to see who made a problematic panel..
and who is to say that *other* [shudder] companies have the same panel problem!

is it *really* a ips or is it a cheaper variant.. or even a tn panel sold *as* a ips or va or whatever.....

paranoids are often Made, not Born!

betcha this "problem" also existed with the crts too!

just go read some of the stuff on the avs forums!!

but here is a Good One!


http://www.digitalversus.com/samsung-tvs-panel-switching-saga-n15168.html
Samsung TVs in Panel Switching Saga?


Investigations carried out by our French sister site have confirmed that different sized televisions in one product range aren't necessarily fitted with the same display panel. In fact, one range can feature screen panels made by several manufacturers. But can different panels also be found in one sole model of TV? While our sister site's investigations haven't uncovered a full-scale panel lottery, other sites, it seems, have already highlighted this kind of problem

A 'panel lottery' is when one same product sold under the same model number is fitted with a selection of different screen panels.

This can be particularly annoying for consumers, as buying a TV basically becomes a complete gamble.

•Winners get a good-quality panel.
•But for losers it'll be a different story, as everything from the colours, responsiveness and viewing angles to the power consumption and more can be totally different.

In a panel lottery, a TV may have the same name, an identical design and be sold at the same price, but its quality will actually vary (sometimes considerably) from one batch to another. And yet, the different products still come covered in stickers and labels supposedly guaranteeing quality ...

Several sites have already highlighted cases of panel switching.

HDTVtest and the 'Panel Lottery'
In a recent test of the Samsung 40C580, HDTVtest.co.uk discovered this TV was available with several different panels. Note that this particular TV is only available in the UK, but it looks very similar to the 40C550 recently launched in mainland Europe. In fact, with such similar physical design and spec, could it actually be the same?


The HDTVtest reviewer claims to have seen two 40C580 TVs fitted with PVA panels of different generations (versions 1009 and 1012, manufactured in China and Slovakia respectively). He even thinks it's possible that C580 TVs could exist with panels manufactured by AU Optronics and CMO. Although he reassures readers that those who happen to buy an AUO model will have no problems at all (these panels are known for offering better pixel response than PVA panels), he then warns that CMO panels could prove more problematic.

The reviewer then highlights an interesting issue, as he says these products are not technically designed for sale on the UK market, and that the chance of you actually buying one from a reputable UK retailer is very slim. We've already seen this when investigating similar problems in monitors, when we found that batches with CMO panels were not intended for sale in Europe. The few models that do slip through the net will undoubtedly be grey imports that some unscrupulous resellers and wholesalers pick up as cut-price jot lots in Asia and then sell on in Europe under the same name as their more expensive counterparts.

The main culprits in such cases are the resellers, who usually defend their actions (and we've heard it first-hand) with two main arguments: that there aren't enough European models available over here (which can often be true, supplies can dry up, even for the most popular ranges); and their need for higher profit margins. The manufacturer is still not entirely innocent in all this, however. How can a manufacturer justify marketing products with such variable characteristics under one same name, even if they are intended for sale in different countries? How can this still be possible?
Click to expand...

freestone: hmmmmmm is *THIS* why many European people seem to get PWM s2440ls?!

Major Russian tech review site iXBT has also been investigating a panel lottery, which has got them just about as riled as us.

They specifically target the Samsung C530/C550 and C570 series TVs which, in Russia, seem to be randomly equipped with PVA panels, MVA panels by AUO or MVA panels by CMO.

AVSforum Panel Lottery List 2009
The question of different panels appearing in one same model of TV seems to have been around for a while. Last year, AVSforum grouped together all the information they had on the subject into an impressive and stunningly long list of panels used in various models of Samsung TV.

They focused mainly on the B650 and B750 series (one of which we tested back in 2009).
Click to expand...

that avs forum link is here.
http://www.avsforum.com/t/1178897/samsung-s-a-c-panel-differences-2009-lcd-line-up

-------Introduction--------
I've been trying to tell people about this 'panel' issue; but many people disacknowledge and disprove.
Truth be told; Last year, Samsung started using AMVA (AUO) and SMVA (CMO) panels, but only with the A630 model and down - A650 and up used strictly SPVA panels. This year, every set seems to involve more than one panel including sets higher than '630'. (Based on all 2009 CCFL-LCD Lineup)
Some do acknowledge about this issue to an extent; but believe there isn't ANY difference. Sorry, but there is a difference and people need to know about it.
Click to expand...

there.
I may have actually FOUND why so many european people have problem s2440ls! for whatever reason, an inferior panel is used there!

that avs link, above, has some good reading.

freestone
 
Last edited:
hi all.

from my previous post.


http://www.digitalversus.com/samsung-tvs-panel-switching-saga-n15168.html

The reviewer then highlights an interesting issue, as he says these products are not technically designed for sale on the UK market, and that the chance of you actually buying one from a reputable UK retailer is very slim. We've already seen this when investigating similar problems in monitors, when we found that batches with CMO panels were not intended for sale in Europe. The few models that do slip through the net will undoubtedly be grey imports that some unscrupulous resellers and wholesalers pick up as cut-price jot lots in Asia and then sell on in Europe under the same name as their more expensive counterparts.
Click to expand...

I find this information very very Disturbing!!

I read here, "many of the "good" panels are not supposed to be for sale in Europe, and this also means that for this same type of "banned" panels, this switching might occur across
many, if not most, manufacturers!"!

why are they Banned?! lack of supply?
power cycle/voltage/amps incompatibilities?!

....that first poster who got a PWM, a severe case of it, and reported "awful" flickerings on all light settings, he also reported that there was no serial number on the back of his monitor! he comes from Sweden.

I can see it now, he buys from a shipper and this shipper ships from a Asian knock-off factory!

but what concerns me here and yes, i am fanning the flames of paranoia here, folks, but what concerns me here is that this problem, in Europe at least, might not be limited to *a* monitor model or even to *a* company!
--even if you buy from "zzzz" brand, you still might be screwed.

the only suggestion here is to go with camera in hand and techniques at the ready, to a store where there is a model on display. IF that passes, then insist on a return-if-not-right, as even different boxes, on the shelves, might have different panel origins!! Be better to buy from a trusted place, even if more expensive. Better even yet is to have the tech people, like of the Geek Squad at Best Buy, open it up and hook it up and then you look very carefully for anything amiss!

freestone
 
freestonew said:
i s-l-o-w-l-y, slowly moved my finger back and forth and then sped my movement up a bit.
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What do you mean slowly? You have to swing the pen fast to be able to see the afterimages. Like 150 inches per second for 300hz PWM frequency. And have it on low brightness too. 0-30% or so.
 
CrabJuice said:
What do you mean slowly? You have to swing the pen fast to be able to see the afterimages. Like 150 inches per second for 300hz PWM frequency. And have it on low brightness too. 0-30% or so.
Click to expand...

do you know that the visual cortex and the retina processes in stages?



http://en.wikipedia.org/wiki/Saccade

apparently the retina and the cortex runs out of "chemicals" so that there has to be a recharging. thus we see in micro-jerks. move your eyes across a white field, slowly, and the Jerking can be seen.

freestone
 
CrabJuice said:
What do you mean slowly? You have to swing the pen fast to be able to see the afterimages. Like 150 inches per second for 300hz PWM frequency. And have it on low brightness too. 0-30% or so.
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right crabjuice. freestone take any camera put it in sports mode or high shutter speed and point at your screen keeping the screen at 30-40% brightness then if you dont see any flicker just record it and post it on the net. put a link here.

and there are plenty of PWM screens floating in ALL markets and dell never marketed s2440L as PWM free to begin with. Even high end pricey models use PWM. Its just about the end user being ok with it or not.
 
clonalvex said:
It is the the pattern of the background on that page. Go to the Lagom LCD test site, (Inversion page) http://www.lagom.nl/lcd-test/inversion.php, for a more dramatic effect. Number 5, 6a and 6b are similar with a horizontal line pattern.
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sure but this doesn't happen when i connect to the s2440L VGA port. or even when i connect another monitor via hdmi-hdmi.

so this is a s2440L hdmi port issue from what i can see.
 
dopple said:
can you answer my last post about the hairlosstalk.com website?
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I went that day but i thought maybe web site was a mistake . . . I dont see and flicker even with my lowest setting . me being paranoid Ive been looking hard but notha
 
the_real_7 said:
I went that day but i thought maybe web site was a mistake . . . I dont see and flicker even with my lowest setting . me being paranoid Ive been looking hard but notha
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okay cool did you scroll the frontpage of that site? this is not backlight flicker ... but flicker due to pattern of the background..
 
dopple said:
okay cool did you scroll the frontpage of that site? this is not backlight flicker ... but flicker due to pattern of the background..
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ok I see what you talking about dopple , yes there is a very slight dimmer on that page when i scroll down , but if i didnt pay attention real hard i would of never noticed .
 
Would this be considered PWM flicker? If this is, I guess that I'm just fortunate that it does not affect me. BTW, this is my S2440L bought at Best Buy.
 
Got my Dell S2740L 27 inch Monitor from UPS today, hooked everything up and was not impressed at all by the 1080p res. I've been using a Dell 2407 for at least a couple of years and this was not the upgrade I was looking for. Everything on the screen was just big, and didn't feel right. I have now boxed everything back up and will be returning it.

Looks like I'll be shopping for a 27 inch 1440p now.

Here it is on the left next to my 2407.
35ipqax.jpg
 
dR.Jester said:
Got my Dell S2740L 27 inch Monitor from UPS today, hooked everything up and was not impressed at all by the 1080p res. I've been using a Dell 2407 for at least a couple of years and this was not the upgrade I was looking for. Everything on the screen was just big, and didn't feel right. I have now boxed everything back up and will be returning it.

Looks like I'll be shopping for a 27 inch 1440p now.

Here it is on the left next to my 2407.
35ipqax.jpg
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well you would have been disappointed with any 1080 27"er then... doesnt say much about the specific monitor you got.

you probably didnt figure out your own requirements before placing the order.
 
I don't get it, what kind of flicker is that? I read on a big reviewer webpage that tested S2440L for pwm flicker and they claim that they couldn't detect any. How come in that video there is pwm flicker? Is it 100% sure that the monitor in the video is Dell S2440L?
 
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