C24FG70, Pixel Inversion?

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hellsrage
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C24FG70, Pixel Inversion?

Post by hellsrage » 28 Mar 2017, 18:47

I decided to buy a 144hz monitor recently and after looking around I chose the C24FG70. The unit I received is a September model, which as I understand has some issues with FreeSync, however since I'm currently running a 1070, that not really a big deal for me.

What is a big deal is apparently pixel inversion, in my case it seems that any time there is motion on the display you can see a fine pixel grid for a fraction of a second, in games, videos, streams, web browsing ect.

From what I've read this is fairly common? But surely at some point it there has to be an exception, is it really this apparent, to the point of being very distracting?

I did try out the inversion artifacts test on here and the checkerboard pattern had what seemed like vertical scan lines with some fast flickering, with the colored bars it seems that blacks/grays seem to show it more than other colors, actually I'm not sure why I didn't think of this before but here is a picture of what it looks like.

If you look at the the darkest gray colored bars you can see what I'm seeing when I watch something on Netflix or play a game.
Image

I think I also may have captured it a little bit in motion at the top of this video of a menu scrolling in game, but I'm not familiar with any of this.
https://gfycat.com/IdleWeeFirebelliedtoad

So is this an extreme case or is this really normal? Because unless this is a defect, I'm not sure 144hz is worth it when the quality of the image is hit that hard. And no setting in the OSD has help reduce how pronounced it is as well.

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Re: C24FG70, Pixel Inversion?

Post by CRTguy » 28 Mar 2017, 18:50

I saw a similar behavior with the PG258Q, where there were faint vertical scan lines on still images that would suddenly be super accentuated when there was motion around them. I found it extremely distracting and annoying to deal with. Maybe it was a different problem than this, but I did see distracting lines through images during motion. If anyone can clarify if this is some kind of "new standard" for 144hz+ monitor or certain monitors, that would be good information to know.

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Re: C24FG70, Pixel Inversion?

Post by RealNC » 28 Mar 2017, 21:59

CRTguy wrote:If anyone can clarify if this is some kind of "new standard" for 144hz+ monitor or certain monitors, that would be good information to know.
I don't think so. This sounds more like a defect and cause for RMA. I have a "cheap" AOC 144Hz FreeSync lying around and it's not doing that. Neither does the 165Hz ViewSonic I'm using.
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hellsrage
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Re: C24FG70, Pixel Inversion?

Post by hellsrage » 28 Mar 2017, 22:24

Any comment on my situation? Any of your monitors ever had what I'm seeing?

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Re: C24FG70, Pixel Inversion?

Post by Chief Blur Buster » 29 Mar 2017, 14:44

hellsrage wrote:Any comment on my situation? Any of your monitors ever had what I'm seeing?
Most of my "Better Than 60Hz" TN monitors show a form of inversion pattern of some kind during certain tests. Some much worse than others.

It's apparently a normal part of many monitors -- but very panel dependant (TN vs IPS vs VA). IPS tends to be much better in this respect. High-refresh-rate TN is very prone to this, especially during strobe mode. Inversion patterns are most easily seen at odd pixel-motion-steps (3pps,5pps,7pps, etc) in the several selectable Inversion tests at http://www.testufo.com/inversion -- sometimes the inversion pattern of TestUFO does not match the inversion pattern of your monitor -- so you have to experiment a little. Check out the Lagom Pixel Walk patterns to determine your inversion pattern too.

For example, a neat behaviour of inversion is discoloration. Most 144Hz TN-panel monitors show green-purple when viewing http://www.testufo.com/inversion .... Sometimes inversion patterns show as discoloration instead of a pixel checkerboard pattern...

RMA is possible, but 95% of the time, you get something equal or worse. Do RMA only if you test multiple monitors (like a friend's C24FG70) and they all show better than your monitor. Then odds are you have mis-calibrated voltage inversion in your panel (a bad panel) and the panel lottery is more likely to win.
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Re: C24FG70, Pixel Inversion?

Post by hellsrage » 29 Mar 2017, 16:34

Chief Blur Buster wrote: RMA is possible, but 95% of the time, you get something equal or worse. Do RMA only if you test multiple monitors (like a friend's C24FG70) and they all show better than your monitor. Then odds are you have mis-calibrated voltage inversion in your panel (a bad panel) and the panel lottery is more likely to win.
I bought it on Amazon directly from Amazon, so I think I'll put in a return and order a new one and if the new one has the issue as well I think I'll just stick to my crappy monitors for now.

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Re: C24FG70, Pixel Inversion?

Post by Chief Blur Buster » 29 Mar 2017, 17:47

hellsrage wrote:
Chief Blur Buster wrote:I bought it on Amazon directly from Amazon, so I think I'll put in a return and order a new one and if the new one has the issue as well I think I'll just stick to my crappy monitors for now.
We'll be resuming testing monitors this year (2017) so, we will finally have much more comparative data on strobe crosstalk between a wider variety of different monitors. It will take time, given we've only relaunched the new 2017 www.BlurBusters.com ...
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Re: C24FG70, Pixel Inversion?

Post by RealNC » 29 Mar 2017, 23:06

hellsrage wrote:
Chief Blur Buster wrote: RMA is possible, but 95% of the time, you get something equal or worse. Do RMA only if you test multiple monitors (like a friend's C24FG70) and they all show better than your monitor. Then odds are you have mis-calibrated voltage inversion in your panel (a bad panel) and the panel lottery is more likely to win.
I bought it on Amazon directly from Amazon, so I think I'll put in a return and order a new one and if the new one has the issue as well I think I'll just stick to my crappy monitors for now.
As I already mentioned, none of my monitors have this issue.

I'm not sure what Chief is talking about, but this is NOT normal outside of specially crafted test images.

If a monitor has these lines 100% of the time no matter what is displayed, IT IS BROKEN. LCD monitors would never have become popular if this was a normal thing.

If all units of that model have the issue, then I have to wonder why they are not recalled, or why they were allowed to be sold in the first place. In any event, you should then look into other models.

Again: this is NOT normal for LCD monitors.
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Re: C24FG70, Pixel Inversion?

Post by Chief Blur Buster » 30 Mar 2017, 02:03

RealNC wrote:I'm not sure what Chief is talking about, but this is NOT normal outside of specially crafted test images.
Actually:

https://rog.asus.com/forum/showthread.p ... in-3D-mode

https://www.pcper.com/reviews/Displays/ ... CON-Artifa

http://forums.blurbusters.com/viewtopic ... ion#p24657

http://3dvision-blog.com/9009-some-3d-v ... n-3d-mode/

etc,etc,etc. (Need I keep going???)

It's really a common problem. The point is, RealNC, is if you do not own a C24FG70, how do you know what's "normal inversion" is for a C24FG70? You own a C24FG70? Or can you provide references to what's normal for a C24FG70? I'm curious -- because I'd like to know too.

The fact is, what I see in those photos is inversion (LCD electronics doing the voltage-balancing alternating positive/negative voltages, of alternate-pixels at alternate-refresh cycles -- that's called "inversion"). Definitely. It's explained in many articles if you google "LCD inversion" (and you see the +/- voltages in Google Images, too). Inversion can create very subtle, very faint LCD artifacts (normal, consistent). Sometimes more visible than others. Sometimes blatant or aberrative (poor panel lottery). This image looks somewhat normal-ish for certain monitors, but it might actually be abnormal (or not!) for a C24FG70......so please provide definitive references it's NOT abnormal for a C24FG70....

But, yes.... The big question is -- "is that abnormal inversion" For that particular monitor?

Plus, it doesn't need specially crafted test patterns. I see a slight amount of inversion (faint checkerboard-pixel-patterning) on my PG278Q during 120pps -- e.g. http://www.testufo.com/#test=photo&phot ... pg&pps=120 .... or when super-slow-turning in FPS games, or at odd pixel rates (e.g. 1ppf, 3ppf, 5ppf, etc). It's not noticeable at arm's length viewing distance, but it's very noticeable if I lean slightly closer. Some monitors have inversion worse than others.

TN monitors are much more prone to inversion issues than IPS/VA monitors, and more than half of TN panels have at least faint inversion during 3D glasses mode. But actually gets visible during specific odd-ppf motionspeeds or during certain speeds of mouse-turning in high-primary-color-solids games (such as Borderlands) which can get distracting by some people if artifacts from normal LCD inversion is more than "very faint".

The VG248QE does a really good job at keeping inversion artifacts nearly invisible, but for a long while yet VG278HE actually exhibited worse inversion artifacsts than VG278H -- had some amplified inversion artifacts that were not solved after 5 exchanges (so the panel lottery was not easily won for that particular model). It's hard to win the panel lottery sometimes.

YEs, keep returning the monitor if you must -- but not without saying that exchanging is guaranteed to solve the problem, because sometimes it's just like average strobe crosstalk, or a TN viewing angle issue. It's hard to win the panel lottery with traits that seem to remain constant between panels (e.g. strobe crosstalk, TN viewing angle, inversion artifacts). Some monitors are really good, and some monitors are average.

Some people really notice inversion artifacts really quickly, other people do not.
Some people are more colorblind-ish than others, others get annoyed by poor colors, while some do not.
(Color sensitivity varies an unexpectedly large amount between people, much like how hearing varies between people -- and 8% are insensitive enough to be called color blind)
Some people don't even notice gamma nonuniformities, while others really get totally annoyed by it.
Some people get more motion blur headaches (immune to flicker headaches), and some people get more flicker headaches (prefer motion blur).
Likewise, some people see certian artifacts more easily such as faint inversion, or VA gamma nonuniformity.
The bottom line: Everybody's human vision system is different.
Inversion is often faint-ish -- but it isn't always to everyone.

So....
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Re: C24FG70, Pixel Inversion?

Post by RealNC » 30 Mar 2017, 02:24

I think we're over-analyzing this. Here's what I'm saying:

If I buy a monitor and the image is full with lines when there's movement, why would I not think the monitor is broken?

Some people seem willing to accept image corruption as "normal." Well it's not. A monitor is supposed to display what you feed into it. It's not supposed to add extra stuff on its own. I can understand that there can be corner cases (and demonstrated through specially crafted "pixel inversion test" images.) But if you get that effect with everything, all the time, I mean common. That's a poorly made/designed product.
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