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Old Jun 18, 2013, 11:38 PM   #26
Chippy99
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To be honest, I have no clue why the world seems to rave about IPS panels. OK so some of them have a wide colour gamut if fitted with suitable backlight (but then again so do PVA/MVA panels).

But in general, compared to PVA (and derivatives), IPS has:

Lousy uniformity
Clouding
Very poor black levels and contrast ratio
IR issues.

I have an old EIZO display that has 20,000 hours on it and it suffers from none of the above and frankly murders the iMac display quality.

Last edited by Chippy99; Jun 18, 2013 at 11:45 PM.
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Old Jun 19, 2013, 03:52 AM   #27
WilliamG
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Originally Posted by edry.hilario View Post
so what kind of "image persistance" is apple talking about then? could you should me an example. I just want to know the difference. Also what would you say to the rest of us who have and are experiencing similar things ? can it be all a coincidence?? especially me and all the machines ive tested?? theres no reason why i would be making this up william. Why would ALL the machines ive tested exhibit some sort of IR. Not to the degree of op's machine but to some mild degree.
Mild image retention usually manifests itself in the form of faint vertical/horizontal lines - usually from menu bars/windows left open too long etc.

Think about it. What percentage of users are complaining about image retention? A teeny, tiny amount. What percentage of iMac users don't have image retention? Most of us. If this were an issue that affected every iMac, don't you think we'd see more about it?

Now, why would ALL your machines exhibit some sort of IR? That's a VERY good question. And that's not uncommon, it seems. You're not the first person with an iMac to have image retention on multiple units. I'd love to know what's going on to make that happen, but alas I have no answer to that one. All I know is - I positively torture my 27" 2012 iMac, just like the 27" 2009 iMac before it, and I've never, EVER seen any image retention.

I would love to know what's going on with some people's systems with horrendous image retention, though. If you ship me your iMac, I can certainly test it for you.

----------

Quote:
Originally Posted by Chippy99 View Post
To be honest, I have no clue why the world seems to rave about IPS panels. OK so some of them have a wide colour gamut if fitted with suitable backlight (but then again so do PVA/MVA panels).

But in general, compared to PVA (and derivatives), IPS has:

Lousy uniformity
Clouding
Very poor black levels and contrast ratio
IR issues.

I have an old EIZO display that has 20,000 hours on it and it suffers from none of the above and frankly murders the iMac display quality.
Lousy uniformity: Sometimes.. (certainly not always)
Clouding: Pretty often
Poor black levels and contrast ratio: Absolutely
IR issues: Occasionally.

But the color accuracy is excellent...

All panels have their issues. What panel type is your old Eizo display?
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Old Jun 19, 2013, 08:40 AM   #28
Chippy99
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Quote:
Originally Posted by WilliamG View Post
Mild image retention usually manifests itself in the form of faint vertical/horizontal lines - usually from menu bars/windows left open too long etc.

Think about it. What percentage of users are complaining about image retention? A teeny, tiny amount. What percentage of iMac users don't have image retention? Most of us. If this were an issue that affected every iMac, don't you think we'd see more about it?

Now, why would ALL your machines exhibit some sort of IR? That's a VERY good question. And that's not uncommon, it seems. You're not the first person with an iMac to have image retention on multiple units. I'd love to know what's going on to make that happen, but alas I have no answer to that one. All I know is - I positively torture my 27" 2012 iMac, just like the 27" 2009 iMac before it, and I've never, EVER seen any image retention.

I would love to know what's going on with some people's systems with horrendous image retention, though. If you ship me your iMac, I can certainly test it for you.

----------



Lousy uniformity: Sometimes.. (certainly not always)
Clouding: Pretty often
Poor black levels and contrast ratio: Absolutely
IR issues: Occasionally.

But the color accuracy is excellent...

All panels have their issues. What panel type is your old Eizo display?
S-PVA. I note even Eizo have largely shifted to IPS panels though. Whether its a cost thing or what, I don't know. But from my perspective the S-PVA based EIZO was better in every parameter, apart from colour gamut, which as I say is more down to the backlight than anything else. Maybe out of the box colour accuracy is better on IPS, I don't know, but since I calibrate my monitors anyway that is of no benefit to me.
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Old Jun 19, 2013, 08:57 AM   #29
edry.hilario
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Quote:
Originally Posted by WilliamG View Post
Mild image retention usually manifests itself in the form of faint vertical/horizontal lines - usually from menu bars/windows left open too long etc.

Think about it. What percentage of users are complaining about image retention? A teeny, tiny amount. What percentage of iMac users don't have image retention? Most of us. If this were an issue that affected every iMac, don't you think we'd see more about it?

Now, why would ALL your machines exhibit some sort of IR? That's a VERY good question. And that's not uncommon, it seems. You're not the first person with an iMac to have image retention on multiple units. I'd love to know what's going on to make that happen, but alas I have no answer to that one. All I know is - I positively torture my 27" 2012 iMac, just like the 27" 2009 iMac before it, and I've never, EVER seen any image retention.

I would love to know what's going on with some people's systems with horrendous image retention, though. If you ship me your iMac, I can certainly test it for you.

----------



Lousy uniformity: Sometimes.. (certainly not always)
Clouding: Pretty often
Poor black levels and contrast ratio: Absolutely
IR issues: Occasionally.

But the color accuracy is excellent...

All panels have their issues. What panel type is your old Eizo display?
I think you cant really say percentage wise you know.. some people dont even notice it at all because is so mild, but is there.... like mine its like you described above its very little but it is still there after a long period of time. And all the machines ive tested NOT just my replacements. Ive gone out of my way to test this thing to make sure ive not just getting screwed. I think you dont see it everywhere because people just dont know. Ive seen people posting here saying stuff like "ive been using my imac for past three months and i just noticed the retention" I think you cant just rule that out.
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Old Jun 19, 2013, 09:08 AM   #30
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Quote:
Originally Posted by jmhart View Post
They seriously need to stop using 3 generation old LG panels.
They need to design something that doesn't have these problems. LG is used in a lot of things, yet I've had far more problems with their panels stuck in Apple stuff than anything else. I don't care what brand of panel goes in there. I only care how the completed unit functions.

Quote:
Originally Posted by Chippy99 View Post
S-PVA. I note even Eizo have largely shifted to IPS panels though. Whether its a cost thing or what, I don't know. But from my perspective the S-PVA based EIZO was better in every parameter, apart from colour gamut, which as I say is more down to the backlight than anything else. Maybe out of the box colour accuracy is better on IPS, I don't know, but since I calibrate my monitors anyway that is of no benefit to me.
IPS typically costs more. The older Eizos used IPS too on most models. The CG211s used IPS, and they were arguably the best displays from that brand. That last statement is completely false. Whenever the topic of color accuracy comes up, it assumes the display is calibrated and profiled properly. Besides the calibration you can do once you own a display amounts to a fraction of what is done at the factory. It's not as accurate. It's just to track the behavior of the display and minimize drift over time via corrections. Some brands have accomplished that to a much finer degree than others. Personally I think Apple's displays are terrible. They're probably the worst thing made by Apple, and in terms of engineering, there is more to it than just the panel chosen.

As for Eizo shifting to LG, the other brands no longer seem to make panels for that market. The prior ones were Hitachi, Mitsubishi, and sometimes NEC. Samsung was used on some of the cheaper ones and the extreme sizes. I saw one of the 30" displays with a PVA panel. The unit I saw looked good, but a major factor with PVA was always viewing angles. It had a lot of gamma shift issues.
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Old Jun 19, 2013, 09:21 AM   #31
Chippy99
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Originally Posted by thekev View Post
Whenever the topic of color accuracy comes up, it assumes the display is calibrated and profiled properly. Besides the calibration you can do once you own a display amounts to a fraction of what is done at the factory. It's not as accurate. It's just to track the behavior of the display and minimize drift over time via corrections.
Can't agree with that. If you have 2 screens, and you calibrate both of them with the white point set correctly and with low Delta E's maybe 2 or under, then you are not going to see better colour accuracy from one screen compared to the other. Calibration by the user is not just "tracking the behaviour", it is minimising colour inaccuracy.

Of course in saying the above, I am assuming identical screen uniformity. Ironically IPS is worse at screen uniformity anyway.
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Old Jun 19, 2013, 10:01 AM   #32
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Originally Posted by Chippy99 View Post
Can't agree with that. If you have 2 screens, and you calibrate both of them with the white point set correctly and with low Delta E's maybe 2 or under, then you are not going to see better colour accuracy from one screen compared to the other. Calibration by the user is not just "tracking the behaviour", it is minimising colour inaccuracy.

Of course in saying the above, I am assuming identical screen uniformity. Ironically IPS is worse at screen uniformity anyway.
Blah. You didn't mention 2 screens. That is just adding a second target. Either way you're trying to maintain static output values on constantly drifting hardware. Either way calibrating regularly will not change the quality of the hardware itself. The way Delta E values are displayed leaves much to be desired too. The accuracy can vary if you change the type of display, colorimeter, or software. Most colorimeters aren't as accurate as you might think. You might want to do some reading or your own tests on this. The entire system of monitor calibration often tends to be good enough, but if it could make a $200 monitor perfectly match the output of yours, Eizo would be out of business.
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Old Jun 19, 2013, 11:28 AM   #33
Chippy99
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Changing the subject somewhat... my 2nd iMac arrived this afternoon.

All I can say is WOW what a difference in screen quality!!! Unbelievable difference.

The one that's going back under RMA had dirt behind the glass, hence returning it. But it also has clouding, leaky backlight and colour uniformity issues.

The new screen has none of these. With the lights off, displaying a black screen it is very uniform with no bleed. There is some colour non-uniformity and the LHS is more yellow than the right but it is MASSIVELY better. And no dust and no stuck/dead pixels. I am very pleased.

Unfortunately the whole screen leans to the left and the power button sticks. But heck, you can't have everything can you.
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Old Jun 19, 2013, 11:46 AM   #34
edry.hilario
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Originally Posted by Chippy99 View Post
Changing the subject somewhat... my 2nd iMac arrived this afternoon.

All I can say is WOW what a difference in screen quality!!! Unbelievable difference.

The one that's going back under RMA had dirt behind the glass, hence returning it. But it also has clouding, leaky backlight and colour uniformity issues.

The new screen has none of these. With the lights off, displaying a black screen it is very uniform with no bleed. There is some colour non-uniformity and the LHS is more yellow than the right but it is MASSIVELY better. And no dust and no stuck/dead pixels. I am very pleased.

Unfortunately the whole screen leans to the left and the power button sticks. But heck, you can't have everything can you.
thats great! Let us know about IR how is it? also i had the same problem with the power button the more you use it will get less sticky. Mine works perfectly now. Or turn it off unplug the machine and press the power button a few times.
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Old Jun 19, 2013, 12:28 PM   #35
WilliamG
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Originally Posted by Chippy99 View Post
Changing the subject somewhat... my 2nd iMac arrived this afternoon.

All I can say is WOW what a difference in screen quality!!! Unbelievable difference.

The one that's going back under RMA had dirt behind the glass, hence returning it. But it also has clouding, leaky backlight and colour uniformity issues.

The new screen has none of these. With the lights off, displaying a black screen it is very uniform with no bleed. There is some colour non-uniformity and the LHS is more yellow than the right but it is MASSIVELY better. And no dust and no stuck/dead pixels. I am very pleased.

Unfortunately the whole screen leans to the left and the power button sticks. But heck, you can't have everything can you.
That sounds much more like my experience with my iMac. Very good uniformity, though I've definitely seen some iMacs that are yellower in various places etc. A slight sag on the screen is not unusual, if it's just a few mm off. If you take a measuring tape and measure from your desk to each side of the iMac (on the very edge), what's the difference between them?

To be honest, though, I've never seen a 100% aligned iMac (mine included). Just how it goes when they screw the stand to the screen. If we had access to the stand, it would be relatively simple to fix I'd imagine.
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Old Jun 19, 2013, 03:56 PM   #36
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Quote:
Originally Posted by Chippy99 View Post
Changing the subject somewhat... my 2nd iMac arrived this afternoon.

All I can say is WOW what a difference in screen quality!!! Unbelievable difference.

The one that's going back under RMA had dirt behind the glass, hence returning it. But it also has clouding, leaky backlight and colour uniformity issues.

The new screen has none of these. With the lights off, displaying a black screen it is very uniform with no bleed. There is some colour non-uniformity and the LHS is more yellow than the right but it is MASSIVELY better. And no dust and no stuck/dead pixels. I am very pleased.

Unfortunately the whole screen leans to the left and the power button sticks. But heck, you can't have everything can you.
I've seen that issue with Apple more than others. I'm glad you got it fixed.
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Old Jun 19, 2013, 04:35 PM   #37
Chippy99
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if it could make a $200 monitor perfectly match the output of yours, Eizo would be out of business.
That's a fair point, I have to say.
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