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

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k2viper
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by k2viper » 11 Feb 2018, 08:21

Chief Blur Buster wrote:That's a hand-propelled mid-air pursuit photograph? (Wave camera, following motion, snap a 4-refresh-cycle (1/60sec) exposure at 240Hz?)
Yes, handwave pursuit, I'm trying my best 8-)
Got some more. Both my cameras (smartphone and ultrazoom) focusing way better with pursuit.

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

Post by Falkentyne » 11 Feb 2018, 20:53

That's very interesting.
Looks a lot like the Benqs worked with a Strobe Phase of 000 and VT tweaks. Lots of crosstalk at the top of the screen but none at the bottom?

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

Post by Chief Blur Buster » 11 Feb 2018, 23:05

k2viper wrote:Got some more. Both my cameras (smartphone and ultrazoom) focusing way better with pursuit.
That's normal, since when you pursuit, the image is essentially almost stationary relative to the camera lens -- giving the camera a reference to focus. However, the recommended way is to lock the focus. On most smartphones that's done via tap-and-hold. That way, it won't keep hunting for focus.

That said, most readers don't nail a rail-less hand-waved pursuit camera correctly -- but you did it (fairly) accurately -- less than 1 pixel tracking error margin at 960pps. Congratulations for being maybe only the 3rd or 4th Blur Busters reader to nail the pursuit camera successfully within that accuracy margin -- without a sliding-camera rail.
Falkentyne wrote:That's very interesting.
Looks a lot like the Benqs worked with a Strobe Phase of 000 and VT tweaks. Lots of crosstalk at the top of the screen but none at the bottom?
Actually, look closer (zoom the bottom image), there's crosstalk.

Remember: This is 240Hz strobed -- so the crosstalk is only 4 pixels apart at 960pps motion speed than the usual 8 pixels apart.

That's still pretty good for 240Hz strobed which is currently unable to fully "cram LCD GtG into VBI between refresh cycles".

LG has come a long way in strobe quality since the 24GM77 days.
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Chief Blur Buster » 12 Feb 2018, 18:23

Do you mind if you can post equivalent photos for 120Hz strobed?

With and without the Large VT tweaks?

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

Post by k2viper » 13 Feb 2018, 02:40

120hz default (no VT tweaks), obvious crosstalk, faint at top and mid, thick at bottom (press @ center of the picture to load full image).

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

Post by k2viper » 13 Feb 2018, 08:34

144hz works with VT 1582, same max VT I found for 120hz. At VT 1600 and higher, strobing just turns off, OSD shows 157hz while its 144hz.

Thick crosstalk at bottom, and fine and faint at top and middle (pics are 144hz strobed VT1582).
240hz shows different - thicker at top, best at middle, thin at bottom.
So 240hz VT1306 still renders to be the best mode I found yet.

If there'll be a way to adjust strobe length (via service menu or DDC/CI), this display would be a gem.

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

Post by ericl » 13 Feb 2018, 10:50

That's nuts, is this monitor available in Canada? Couldn't find it on Amazon.ca, nor shopbot.ca nor canadacomputers.com nor newegg.ca
:|

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

Post by Chief Blur Buster » 13 Feb 2018, 10:54

ericl wrote:That's nuts, is this monitor available in Canada? Couldn't find it on Amazon.ca, nor shopbot.ca nor canadacomputers.com nor newegg.ca
:|
This particular US Amazon seller will ship the 27GK750F to Canada. Not yet available in Canada, alas.
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by dogroll » 14 Feb 2018, 01:04

It looks to be a good strobing implementation overall, I just wonder how much input lag LG's strobing adds. Hopefully almost none like BenQ.

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

Post by k2viper » 14 Feb 2018, 01:39

Almost none, I dont feel any additional input lag @240hz vs non-strobed mode.
Monitor is very responsive overall, I'm fully satisfied with its responsiveness.

I still havent found an advertised Dynamic action sync (DAS) option, same on different (korean) video reviews over the net, I think this option is not showing up on Displayport connection, it may be available only on HDMI or not available at all (probably always on).

"Scaling" in OSD also have 1:1 mode which is featured that no adjustmets are made to the input signal, so it should be the fastest possible mode with no internal scaling/processing.

It would be interesting to compare this model to new Benq XL2740, it should have blur reduction via service menu just like XL2540.

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