LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

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ericl
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by ericl » 26 Dec 2018, 15:28

The pictures are misleading AF because your eyes don't see what cameras pick up. (I think we all know that)

I learned this the hard way back in 2009 when I was reviewing the first Samsung 2233rz monitor (120hz) which showed more images than the 60hz variant in pictures which made it appear bad. In practice, it was infinitely better than 60hz.

The SAME thing is happening again, where the 240hz shows more refreshes (obviously) than a 144hz.

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captain_amn
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by captain_amn » 26 Dec 2018, 15:47

ericl wrote:The pictures are misleading AF because your eyes don't see what cameras pick up. (I think we all know that)

I learned this the hard way back in 2009 when I was reviewing the first Samsung 2233rz monitor (120hz) which showed more images than the 60hz variant in pictures which made it appear bad. In practice, it was infinitely better than 60hz.

The SAME thing is happening again, where the 240hz shows more refreshes (obviously) than a 144hz.
If i understand correctly, shooting with 1/240 shutterspeed should only show but one image, to indicate a clear image @ 240Hz
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Kheri
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Kheri » 26 Dec 2018, 17:25

ericl wrote:The pictures are misleading AF because your eyes don't see what cameras pick up. (I think we all know that)

I learned this the hard way back in 2009 when I was reviewing the first Samsung 2233rz monitor (120hz) which showed more images than the 60hz variant in pictures which made it appear bad. In practice, it was infinitely better than 60hz.

The SAME thing is happening again, where the 240hz shows more refreshes (obviously) than a 144hz.
Sure, but it seems a few of us who got their LG monitor after k2viper got his have worse strobing. You can even compare some of the pics shared in this thread side by side to k2viper's and see they're worse. Strobing crosstalk is supposed to be much harder to notice in game than it is on testUFO, though. the 144hz strobing crosstalk is particularly noticeable, however. I have to say this monitor feels considerably better at higher refresh rates (180+) than lower. Having a gpu and cpu that can push those frame rates is definitely (still) important.

I have to say 1ms persistence to me doesn't seem like it'll be enough for 3D games, even now, actually. Phantom Array effect is probably more noticeable though.

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A Solid lad
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by A Solid lad » 27 Dec 2018, 10:31

In my experience, the XL2740 and 27GK750 both look good on test shots and actual UFO test running in front of me... but when I enter a game like BF3 or CSGO... THAT's where the difference becomes apparent.
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Gregix
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Gregix » 28 Dec 2018, 16:43

ericl wrote:The pictures are misleading AF because your eyes don't see what cameras pick up. (I think we all know that)

I learned this the hard way back in 2009 when I was reviewing the first Samsung 2233rz monitor (120hz) which showed more images than the 60hz variant in pictures which made it appear bad. In practice, it was infinitely better than 60hz.

The SAME thing is happening again, where the 240hz shows more refreshes (obviously) than a 144hz.
Maybe. But seeing bee running screen samsung/beng and lg, lg is worst. Picture is blurry. In game, such as americas army, it makes difference, when u runing, spotting camper by the way on ur left, because hi just stand up to rip ur head off, and I rip his head off or die trying.
And many many times I see on spectator more than guys playing normal 60Hz monitor or g-sync, but without strobing. Especially in corners...just see more. More movement, more pixel changes, because rest of the screen seems static(thanks blur reduction), and only foe is moving.

On the other hand, I just went wild, and bought 55" Oled LG c8, so this year screen, it is fab. Just fab. Watching movies is feast for eyes. Do not game on it though, still testing, but picture is superb, actually maybe I will try recalibrate my Benq to match at lest whites...And has to say, 120Hz on OLED seems similar to 240hz non strobed LGs 27gk750. It is damn to big for gaming for me as I have it like 1,5-2 meters from me.

Damn we need this OLEDs as monitors fast with 120Hz +!!! 24" would be enough for me.
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Chief Blur Buster » 28 Dec 2018, 18:21

Actually, I can tell when strobe crosstalk photography is reasonably accurate or not. It's VERY tricky to correctly photograph, and you should trust me when I give instructions to people on how to photograph display motion blur -- sometimes the photographs are taken wrong, and sometimes the photographs are good enough.
ericl wrote:The pictures are misleading AF because your eyes don't see what cameras pick up. (I think we all know that)
While that is true, it's worth noting that I'm the author of a peer reviewed improved method of photographing display motion blur, see pursuit camera paper and several reviewers now use this technique. It's much more WYSIWYG now, as you can see of this photograph of http://www.testufo.com/ghosting

Originally photographed by Jorim under my instruction, this is (now) my Acer XB252Q in Overdrive Normal, Extreme, and OFF during 240 Hertz at 960 pixels per second.

Image

- Ladder track is WYSIWYG
- Amount of ghosting is WYSIWG
- Amount of blur is WYSIWYG

Obviously, this will often miss some subtle temporal artifacts (e.g. DLP dithering, LCD Inversion) but in fact, those has been even successfully photographed using variants of the pursuit camera technique.

The horizontal ladder track is the temporal test pattern used to make sure it was photographed accurately. If it looks virtually exactly the same on the photograph as you did with your human eyes, then you've got the most accurate possible motion blur photographs. The important thing is that you want long exposure + accurate sync to get as blurless as possible that a long-exposure panning camera photograph (~1/30sec) allows (roughly the approximate integration period of human vision) -- and then voila -- your photograph has the same amount of motion blur as it gave your human eyes. This is the most accurate method of photographing display motion blur and related artifacts such as ghosting/coronas/crosstalk/etc

As you can see.... this is the (mostly) WYSIWYG method of photographing display motion blur. A moving camera capturing multiple refresh cycles is a relatively accurate stand-in for a moving eyeball. A panning or rotating camera is the analog for a rotating eyeball tracking moving objects and is thusly the correctly method of capturing display motion blur (for those who don't understand eyetracking is the majority cause of display motion blur, please see TestUFO Eye Tracking Motion Blur.

My innovative free invention (that replicated a $30,000 motion blur photographing technique, into blogger's hands) -- that other websites now use (RTINGS, TFTCentral, TomsHardware, SweClockers, etc) -- makes display motion blur photography much more accurate. If you want to test using a pursuit camera on a display, read about other websites that use my invention, and then also follow these pursuit camera instructions and also related forum thread.

However, there is one specific situation where static is nearly as accurate as pursuiting, because of the ultrashort persistence time having no chance to motionblur: Strobe crosstalk photography is sufficiently accurate for static photographs as long as you photograph only one refresh cycle worth of strobe backlight flash.
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ericl
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by ericl » 30 Dec 2018, 11:12

Perfect example of photography done right vs photography done wrong.

Yours looks like it was done right.

In the previous example, there are no guide lines (hell, the images aren't even flat, they are taken at an angle) AND it looks like they were taken with a cell phone. In addition, they are also using fine tuning adjustments from another user monitor which might not be the best for his specific monitor.

I know that when I personally tested out the CRU settings suggested, it made the display look worse. The best quality settings I found were actually using the default 'original' scaling + the 'FPS gamer 1' profile that LG set up. (This is after hours and hours of testing, fine tuning, etc).

Kheri
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Kheri » 30 Dec 2018, 17:40

I just want to make it clear that no amount of tweaking changes the crosstalk on *MY* monitor at all. (And, yes, CRU changes are taking effect or else my monitor would not stay blank if I set the VT values too high.) This might be the case on others' as well. Also, k2viper also took his pics freehand. I'm not sure how much it matters, given we can (reasonably) clearly see the strobe crosstalk in the images.

I'm thinking about updating graphics driver and a few other things to get the VT tweaks to take effect... any ideas/suggestions? Try a different cable, etc? Honestly suspect my monitor just won't allow VT tweaks, however minor their benefit would be.

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Chief Blur Buster » 30 Dec 2018, 19:42

ericl wrote:In the previous example, there are no guide lines (hell, the images aren't even flat, they are taken at an angle) AND it looks like they were taken with a cell phone. In addition, they are also using fine tuning adjustments from another user monitor which might not be the best for his specific monitor.
Generally true, though I have found strobe crosstalk photography is much more forgiving for cellphones. Guide lines and pursuiting are not necessary when analyzing strobe crosstalk, with one major caveat: For static photography of strobe crosstalk, it is indeed important that the camera exposure is no more than 1 strobe backlight flash for accurate crosstalk photos, or we get additional duplicate images above and beyond. (Pursuit camera requires several refresh cycles to be exact)

Sometimes you can find evidence that single-exposure of strobe flash happened:
(1) The 144Hz one is definitively single-flash-exposure
(2) The 240Hz has indirect evidence of single-flash-exposure: Part of the 240Hz photo is dark (camera sensor rolling scan artifact) which is excellent evidence of single-exposure photo because if it was multi-exposure, there would not be a dark section. Indeed, the dark section and rolling scan behaviour of a camera sensor does provide some moderate distortion, the amount of strobe crosstalk that I see when zooming in, looks reasonably accurate representaton of blur reduction on 240Hz -- strobe crosstalk is worse at 240Hz than for 144Hz. Also, it is possible the LG monitor overdrive is not adjusted in an optimal way for its blur reduction.

There's a possible error margin in these photos, but the artifacts I see, deem them reasonably accurate-enough photographs for comparative purposes, at least from my own educated analysis due to my familiarity with photography artifacts confirming how the photographs were taken. Albiet subject to sensor rolling-scan distortions and minor deviations from WYSIWYG, it's a roughly accurate approximation of the rough amount of strobe crosstalk found at default settings. I have troubleshooted user setups this way before, with my photograph-analysis smarts.

Also, cellphones can still easily function with amateur pursuit photography for free (without a rail), see new thread including iPad camera pursuit that I have posted.
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nanashi31
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by nanashi31 » 31 Dec 2018, 14:55

After my 3 month adventure in search for a good 240hz monitor these are my findings and i hope they can help . I started with Asus xg258q and noticed some strange vertical lines that appear when i was doing fast movements in Battlefield. After replacing cable/gfx card and did some research i found out that it was a common problem and it was more pronounced the lower the hz used, witch was true in my case since GTA on PS4 was much worse .It was so bad that i almost felt like i was behind prison bars whenever i moved. So after that i went for the 25 inch 240hz Acer counterpart kg251 with.......same results. Switched to Alienware aw2518h and the same problem , no matter the cable or Amd/Nvidia card. They seem to use a panel from the same manufacturer if i am not mistaken .The only monitor i tested without the issue was LG 27gk750f-b.
I only have one question . Does this problem not bother people that like those 25 inch panels? For me it was a dealbraker for sure and was taking away from my experience.
Also, this issue was present in other recent 144 hz TN monitors . And the only 100% way to avoid it was to go IPS . For me IPS isn't an option since the response time gives me a headache .

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