Visible Lightboost ghosting on XL2411T

Ask about motion blur reduction in gaming monitors. Includes ULMB (Ultra Low Motion Blur), NVIDIA LightBoost, ASUS ELMB, BenQ/Zowie DyAc, Turbo240, ToastyX Strobelight, etc.
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HitHolic
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Joined: 26 Feb 2014, 11:39

Visible Lightboost ghosting on XL2411T

Post by HitHolic » 26 Feb 2014, 11:55

Hi everyone, I just wanted to figure out if it's normal that i'm having visible ghosting on the lower side of the monitor when using lightboost. I used this test http://www.testufo.com/#test=blurtrail

I didn't manage to take a decent picture of it, so I'm gonna describe the issue I have similar to what the new Z series is having, except it is just ghosting the line, and not fully displacing it.

Image



Sorry for my bad english, it's not my native language.

Thank you. :D

lol37
Posts: 59
Joined: 24 Dec 2013, 15:29

Re: Visible Lightboost ghosting on XL2411T

Post by lol37 » 26 Feb 2014, 12:06

you could try set the lightboost brightness to 10% and customize timings to enforce the monitor refreshing faster.

HitHolic
Posts: 3
Joined: 26 Feb 2014, 11:39

Re: Visible Lightboost ghosting on XL2411T

Post by HitHolic » 26 Feb 2014, 12:28

lol37 wrote:you could try set the lightboost brightness to 10% and customize timings to enforce the monitor refreshing faster.
It's already set to 10% and I suck at customizing things XD

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Chief Blur Buster
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Re: Visible Lightboost ghosting on XL2411T

Post by Chief Blur Buster » 26 Feb 2014, 14:01

This is actually normal. There's always strobe crosstalk on all strobe backlights (most especially noticeable when framerate matches refresh rate), and it's normal to have more strobe crosstalk for the bottom edge of the screen. Often, you can push the strobe crosstalk below human detectable thresholds.

Go to www.testufo.com/photo and to the UFO Alien Invasion test. This result is good, while result is bad.

What's important is that manufacturers calibrate their strobe backlight to look excellent at the center of the screen, and shift any compromises to the screen edges (caused by timing asymmetry between LCD scanout versus all-at-once strobe backlight flash). This can increase input lag by a millisecond or two, however, the vast majority of strobe backlight users want to see the best motion clarity possible.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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HitHolic
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Joined: 26 Feb 2014, 11:39

Re: Visible Lightboost ghosting on XL2411T

Post by HitHolic » 26 Feb 2014, 14:36

Chief Blur Buster wrote:This is actually normal. There's always strobe crosstalk on all strobe backlights (most especially noticeable when framerate matches refresh rate), and it's normal to have more strobe crosstalk for the bottom edge of the screen. Often, you can push the strobe crosstalk below human detectable thresholds.

Go to http://www.testufo.com/photo and to the UFO Alien Invasion test. This result is good, while result is bad.

What's important is that manufacturers calibrate their strobe backlight to look excellent at the center of the screen, and shift any compromises to the screen edges (caused by timing asymmetry between LCD scanout versus all-at-once strobe backlight flash). This can increase input lag by a millisecond or two, however, the vast majority of strobe backlight users want to see the best motion clarity possible.
Wow thanks for the reply, really helpful and neat, it seems I have a good lightboost then :D

Do you think creating a custom resolution with custom values will help reduce the strobe crosstalk?

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Chief Blur Buster
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Re: Visible Lightboost ghosting on XL2411T

Post by Chief Blur Buster » 26 Feb 2014, 14:42

It won't affect LightBoost as LightBoost already uses partial buffering and accelerated scanout, to create the longer pauses between refreshes. That's to allow more time for LCD pixels (GtG) to finish settling. However, the bottom edge of the screen has less time to refresh (in the dark between refreshes) before the strobe backlight begins to flash. It's believed that ULMB and Turbo240 behaves the same way.

There's a high speed video of LightBoost at http://www.blurbusters.com/lightboost/video

BENQ Blur Reduction behaves differently -- it doesn't use accelerated scanout so a workaround is creating a Custom Resolution (either via ToastyX CRU or via NVIDIA Create Custom Resolution utility) with a large blanking interval (e.g. Vertical Total 1350 during 1080p) will do the job of creating the extra pause between refreshes to finish the LCD pixel transitions (in total darkness) before the strobe backlight flash (seen by eyes).
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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Forum Rules wrote:  1. Rule #1: Be Nice. This is published forum rule #1. Even To Newbies & People You Disagree With!
  2. Please report rule violations If you see a post that violates forum rules, then report the post.
  3. ALWAYS respect indie testers here. See how indies are bootstrapping Blur Busters research!

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