Need some ufo test videos and images for backlight strobing on eve spectrum

Currently on the fence about this monitor and I was wondering if users who already own this monitor can post a video and picture of it’s performance with backlight strobing enabled at the three settings (low, medium and high)

Essentially just track the ufo from the left to the right using a smartphone and take a quick photo when you are in the middle. Do the same for video but you just take a video going from left to right while tracking the ufo.

Ghosting test

Crosstalk test

Make sure you full screen them before taking the vids/pics. :slight_smile:

Hello! Try watching this review: The Best 4K Gaming Monitor? Eve Spectrum Review - YouTube
Around 5:56 is what you are looking for if I understand correctly.

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The author of that review was using an old firmware version according to Blur Busters.


Yea, we need some new info with latest firmware

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That’s correct. I’ve reached out to the youtuber already about the old firmware.

Blur Busters is the inventor of modern pursuit camera display testing — to avoid competing against our users of our inventions we don’t mass-review monitors /ourselves/ (except special editions like GSYNC-101, KSF phosphor, Scanout Latency, etc.).

I know — understandably — many think Blur Busters is a “monitor reviewer” but we’re actually a supplier of tests to monitor reviewers, and services for display manufacturers — — such as teaching masterclasses or panel tuning.

That’s why we rely on the users of our display-testing inventions to do the tests. So sometimes it’s kind of a waiting game for pursuit camera tests.

Many previous attempts at tuning multiple KSF panels failed because of firmware limitations, but Suzhou Lehoi (despite English-Mandarian language communication difficulty) threw all my feature requests straight into the firmware, to the point where I was finally successfully able to tune the panel to be superior to a plasma TV — less ghosting than a plasma TV. With a little DIY strobe tuning touch-up, pursuit camera of Eve 4K144 strobing is superior to pursuit camera of a plasma television. So, writing a special edition may help my case on selling tuning services to future KSF panels by any manufacturer. But Eve is the first successfully strobe-tuned KSF panel, thanks to Suzhou Lehoi managing to implement all the necessary compensatory modifications to the firmware (as much as laws of physics allows), to minimize LG Nano IPS KSF ghosting issue as much as Blur Busters could.

I may do a “KSF Phosphor II” special edition article about “How Much Can Blur Busters Polish A KSF Phosphor Panel Such as Nano IPS For Better Strobing?”, or something like that.

That would get around the “no-competing-against-users-of-my-inventions” rule — but workload is a bit high at the moment at Blur Busters.


Looking forward to your article. I agree with the no competing rule and enjoy all your science classes with monitor display technology and blur reduction. Please keep up the good work and I’ll be patiently hoping that VRR strobing feature request comes through :slight_smile: fingers crossed, that feature alone would probably give eve a leg up.


Better than plasma is good but the ultimate question is does it have less motion blur than without backlight strobing?

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Yes, it does.

(Why do you ask such an obvious question similar to “What color is the sky?”)

This is true regardless of strobe backlight, so I’m very curious why you ask a question – every strobe backlights ever invented has less motion blur than without strobing, when used correctly at framerate=Hz.

But you specifically asked versus non-strobed, which ends up to my brain as if you had never seen backlight strobing based motion blur reduction algorithms before – So if you actually have experience, maybe you need to rephrase the question so I can answer your question better, if you maybe meant “strobe crosstalk” instead of “motion blur”? Just want to be clear so I can correctly answer your question – thanks!

Terminologically, are you taking about some other attribute such as strobe crosstalk, or some other artifact, but might have used the wrong terminology such as “ghosting” vs “coronas” vs “persistence blur” vs “strobe crosstalk” which are all 4 different things.)

But the answer, is yes to all 4, at least in the territory of KSF panels.

Versus other KSF panels
Ghosting = the least ghosting I’ve ever seen on KSF panel
Corona = the least corona I’ve ever seen on KSF panel
Persistence blur = the least persistence blur I’ve ever seen on KSF panel
Crosstalk = the least crosstalk I’ve ever seen on a KSF panel

Versus nonstrobed
Ghosting = much less ghosting than non strobed
Corona = much less corona than non strobed
Persistence blur = All strobe backlights in humankind reduce this
Crosstalk = This is the biggie because non-strobed has no crosstalk, and strobed always has crosstalk (even if it’s only 3% or 1.5% or 1%), so crosstalk is always a downgrade for strobe backlights on all strobed LCDs ever invented in humankind. That is where Blur Busters tuning works very hard to reduce as much as possible, so that crosstalk is not as noticeable.

Fortunately, crosstalk is near zero for screen center, leaving only faint KSF ghost that is hard to see. Now, the amount of crosstalk for top/edge depends on how much refreshrate headroom you choose, and how much vertical totals you decide to do concurrently with refreshrate headroom.

Now, Bigger VT = Bigger VBI = more time for LCD GtG pixel response in total darkness between strobe flashes, like High Speed Video of Strobe Backlight | Blur Busters (old 2014 video)

Reminder: crosstalk double-image is not motion blur

Now, plasmas and CRTs use phosphor that has visible ghosting, while nearly all LCD has no phosphor ghosting at all. It’s only a very few LCDs that have phoshphor-derived ghosting, such as KSF (chemical K2SiF6 doped with Mn4) in the backlight LEDs of a NanoIPS panel, typically manufactured by LG. That’s why I compare to plasmas and CRTs, because many people interested in backlight strobing are of people who’ve seen CRTs or plasmas in the past. So I mention them as a point of reference. :Your question is sometimes asked by younger millenials – maybe should have prefaced “If you have ever seen a CRT tube and a plasma display while computer gaming…”) in order to ground a person with a reference point whereupon to scientifically compare motion blur to. (most younger millenials have not spent significant time playing games on CRTs for example – they were superlative for zero motion blur but they still had a minor amount of green-colored phosphor ghosting for bright objects on black background. Plasmas have yellow-colored phosphor ghosting, while KSF LCDs have red-colored phosphor ghosting for strobe operation)

Certainly not as zero-crosstalk-perfect as say, the Oculus Quest 2 VR LCD, or perhaps, say the Blur Busters Approved 2.0 Certified monitors (but then again none are 4K yet, and currently none are wide-gamut yet).

For more information about the different types of artifacts, see LCD Motion Artifacts 101: Introduction | Blur Busters

This will help you get familiar with the correct terminology for the various different LCD motion artifacts (blur, crosstalk, coronas, ghosting). Be noted, 2,3,4 of them can occur simultaneously (e.g. a crosstalk double image that’s simultaneously a negative-image corona, or a crosstalk hybrid between persistence blur and ghosting (like KSF). Perhaps if you would like to describe the specific artifact you would like less of, I can help give perspective.

Now, if you’re wondering about the artifact in the early YouTube video of the old firmware – that’s strobe crosstalk, not motion blur. I instantly recognize the crosstalk (majority of it is not the cause of KSF), it’s from approximately firmware 100R800 through 100R848 – about exactly the same intensity. But of a sudden, firmware V100R852 and newer, has approximately 1/10th as much strobe crosstalk. Big improvement jump there. Some reviewer needs to properly test that.

Anyway, that’s why I reminded Eve to make sure to install the latest firmware thereafter, to any units sent to reviewers, if they want to review the Tuned by Blur Busters strobe.

Now, if this is all new to you, strobe crosstalk is caused by LCD GtG being unfinished in the interval between refresh cycles. LCD is getting faster and it’s becoming easier to cram the GtG elephant in the drinking straw of the gaps (VBI) between refresh cycles. But KSF does throw a monkey wrench into this ability.


These are artifical PhotoShopped examples of crosstalk photography, to mathematically show incompleteness of LCD GtG pixel response cascading into a strobe crosstalk artifact.

  • If GtG only finishes 75% in dark period between refresh cycles, you get 25% crosstalk.
  • If GtG only finishes 90% in dark period between refresh cycles, you get 10% crosstalk.
  • If GtG only finishes 97% in dark period between refresh cycles, you get 3% crosstalk.
  • If GtG only finishes 99% in dark period between refresh cycles, you get 1% crosstalk.

LCD GtG pixel response (GtG = grey to grey) is a pixel slowly fading from an old color to a new color. For each of the pixels on the display. If you are unfamiliar with GtG, please read GtG versus MPRT: Frequently Asked Questions About Pixel Response On Displays | Blur Busters

Also, not all pixels refresh at the same time on any LCD ever invented, see Understanding Display Scan-Out Lag With High Speed Video | Blur Busters

So the problem causing strobe crosstalk double images is caused by laws of physics – you’ve got 2 lags going on (scanout lag and GtG pixel response lag) so you have to hide both of these lags in an unusually long blanking intervals to reduce the crosstalk at the screen top edge and screen bottom edge.

There’s more crosstalk at top/bottom edge because there’s less time of the backlight being turned off since the pixel started its GtG pixel transition (the “crosstalk band” is an interference band caused by law of physics, of the sequentialness of LCD refresh, and the globalness of whole-backlight flash). This affects all LCDs.

Fortunately, I also provide an adjustable strobe phase, so you can move the band almost offscreen. And if you use a lower Hz with a larger VBI (e.g. 60Hz QFT large VT mode), you can have top/center/bottom almost identically clear on the Spectrum. That’s since a faster scanout (e.g. 60Hz refresh cycle sweep-refreshed top-to-bottom in a mere 1/144sec) makes the LCD more closely resemble a global-refresh display than a sequential-refresh display.

Now, I realize this is educational STEM stuff (science, technology, engineering, math), but hopefully this helps explain the cause of strobe crosstalk better, assuming that is what you are referring to (instead of “motion blur”).

So, it’s possible that an old firmware can have 25% crosstalk, and an upgrade of firmware can reduce that to 3% or 5% crosstalk. This is the magnitude of improvement between V100R848-and-older, as well as V100R852-and-newer, so I was a bit disappointed the dominoes didn’t finish falling completely yet (myself, my staff, Suzhou Lehui, their staff, the factory, and then finally Eve to ship – it’s a dominoes from the development desk to the mass production assembly line and shipment company). But reviewers can now firmware upgrade, so that’s the great thing. It is what it is – and at least any newer monitors sent to reviewers nowadays, now already has the latest firmwares.


You answered my question. Sorry for my phrasing I should have given more context. Some of the earlier reviews mentioned the backlight strobing mode look worse than without so I wanted to ask if it was because of the inherent issue with the red phospher but you are correct, they had an old version of the firmware so they wouldn’t really show how good or bad the strobing is in their review.

I have seen CRT monitors and plasma but never really engraved the motion clarity they offered until after we got rid of them all :frowning:

I deeply appreciate the time you take to write all this info and thanks again for always answering my questions. Yes I am considered about the crosstalk on this monitor but knowing it was tuned by blur buster gives me confidence it was tuned the best it could be. I hope the same will happen for the QHD 240 Hz option in the near future.


No worries!

Perhaps I can help some other forum member become a hobbyist DIY monitor reviewer? Allow me:

DIY Pursuit Camera: End-Users of Spectrum Can Share Pursuit Camera Photography!


The Blur Busters pursuit camera technique is a method of making it easy to capture WISYWIG photography of display motion artifacts including motion blur, crosstalk, ghosting, coronas, etc.

The magic sauce is the Sync Track, which looks like a horizontal ladder at TestUFO: Ghosting … It’s a temporal test pattern designed to capture camera tracking accuracy directly into the resulting photograph of display motion artifacts.

Pursuit camera is a peer-reviewed display testing technique invented by me:

Many display reviewers use it:

But it’s actually surprisingly easy.

This used to be a $30,000 device, but I single-handedly built it at home with less than $100 of homemade components. Now today, it’s possible to do for just a mere $0 – end users can do pursuit camera now! It only requires practice. Some people learn in under 15 minutes, other people take 2-3 hours to practice.

So you can use my display testing invention for free. Be your own DIY monitor reviewer! (If you already have an Eve Spectrum 4K144).

Rail-Free Pursuit Camera with iPhone/Galaxy

By the way, existing Spectrum users can do DIY pursuit camera too – end users are now becoming self monitor reviewers. There’s easy instructions to turn an iPhone and a Galaxy to a pursuit camera:

The pursuit camera discussion forum is:

An example explaining how the sync track at TestUFO: Ghosting works:

Stationary Camera Example: Not Equal To Eye Tracking

Look at TestUFO: Ghosting with the horizontal ladders between UFOs.


Pursuit Camera Example: Equal To Eye Tracking

Look at TestUFO: Ghosting with the horizontal ladders between UFOs.


Semi Self Explanatory YouTube

Now we watch a video recording to see stationary vs motion. Watch how the ladder appearance changes!

If one of you already has extensive experience, you could privately send me a video link to your unlisted pursuit-attempt YouTube, and I can help teach you how to operate a pursuit camera, and once it’s successfully working as accordance to rail-free pursuit camera instructions – then can post the pursuits here.

Best to download a SLR-style camera app to your iPhone/Android, and use these settings:

Computer Settings

  • Run TestUFO: Ghosting in any recent web browser
  • Don’t run background software any lively browser tabs during TestUFO
  • Make sure it says READY first before you proceed
  • Now start your smartphone running

Note that Windows DPI is best 100%. If you needs bigger UFOs, use 1080p + pixel perfect scaling, is preferred over blurry UFOs at 125% or 150% DPI.

Camera Settings To Use iPhone/Galaxy as Pursuit Camera

  • Mode: VIDEO instead of PHOTO
    (video is just essentially burst-photography to be easy to get 1 good pursuit photo)
  • Distance from screen = Same as human head and screen (a bit closer is OK, may be easier with smartphone camera)
  • Lens to use of multilens camera = Narrowest angle lens (or optically zoom a bit closer, so the UFOs are bigger on the smartphone screen – I suggest zooming to focus on just middle row of TestUFO: Ghosting but try to avoid digital blurryzoom)
  • White Balance = 6500
  • Focus = fixed
  • ISO: Adjust until it’s normal brightness and not too dark/too bright
  • Saturation Mode = disable any color-boost or vibrance modes
  • Video resolution: Highest bitrate you can get for your exposure per frame.
  • Video frame rate: 60fps or higher for 240Hz+, 30fps or higher for 120Hz+, 24fps or lower for 60Hz. This gives you enough room to adjust camera exposure per frame.
  • Exposure Per Video Frame = two, three or four refresh cycles* … Preferably four, but low refresh rates make this hard (long exposures + shaky hands).
  • Make sure not too bright: whites are not clipped
  • Make sure not too dark: blacks are not clipped
  • Make sure not too satured: color clipping

For iPhone, I use “ProCam” or “DSLRCamera”. Both camera apps turn any iPhone into a reliable pursuit camera.

*Sync track is designed for 4 refresh cycles to mimic human vision integration (aka refresh cycle stacking to get WYSIWYG artifacts photographed). But doing pursuit camera at 60Hz may be easier with just 3 refresh cycles (1/20sec exposure) rather than 4 refresh cycles (1/15sec).

When you video while turning your office chair – keep your body stiff with both of your arms outstretched – holding your smartphone with both hands – spin slowly from left to right following the UFOs. Repeat a few passes. Now you’ve captured maybe 1000 freezeframes, we just used video as equivalent of overkill burst shooting. Now launch your favorite single-stepping video player (finger swipe) to find the best freezeframes. Save or screenshot those freezeframes. That’s your “pursuit camera photo”. Then post it here in this thread. (…Screenshots of a paused video is OK, more hacky than direct freezeframe-save available in certain downloadable video file players or transferring to PC first, but it’s easy end user DIY we’re just doing here that does not require a computer…)

But don’t be rush to post – keep practicing on any monitor (Spectrum or otherwise) before finally doing the Spectrum.

How to Interpret Inaccuracies In Pursuit Camera Tracking Via Sync Track Disjoints


How to Interpret Black Gaps in Pursuit Camera Sync Track in Resulting Photos


From thread:

TL;DR: Free $0 Rail-Less iPhone/Android Pursuit Camera

You just use the smartphone you already have. That’s it!

Rail-less hand-wave pursuit camera is done by holding your iPhone/Galaxy with both outstretched arms in portrait mode (hold with both hands for stability) while slowly spinning your computer chair tracking the UFOs. This makes your human arms much more stable, combined with the fact shooting video gives brute force of hundreds of freezeframe photos that one might be accurate by chance to be a valid pursuit camera photo.

You use video instead of photo mode, so you can get 1000 freezeframes of shaky hands. Sometimes 1 or 10 freezeframes have perfect pursuit camera photography (just like a rail). The sheer overkill burst-photography sample rate of using video recording, compensates **

The sample-rate overkill of video compensates for the lack of a rail, making the $0 DIY pursuit camera possible. Also, back in 2012, most smartphones were not good enough, but today, most recent smartphones are now good enough to be used as a pursuit camera. The $0 free pursuit camera, where a hobbyist at home does what a $30,000 device did fifteen years ago.

If you register for Blur Busters Forums to post messages at Pursuit Camera Forum Pursuit Camera Testing of Display Motion Blur - Blur Busters Forums – I’m happy to help train you on how to use a pursuit camera – for FREE (companies pay me over $1000 for this training service). A perk of the Blur Busters Forums is I give free forum training of pursuit cameras to new display reviewers, or even DIY hobbyist display testing – you can do it! You can train on any different monitor you wish (if you want to be neutral about sharing Spectrum videos without sharing to me first).

End Users Can Become Monitor Reviewers In Under 30 Minutes!

Hopefully this is enough for another forum member to share pursuit camera images (DIY rail-less smartphone camera)


Right now since I need to use Freesync for my games, I don’t think I’m able to take advantage of your tuning. Looking forward to the upcoming VRR/Freesync tuning update though!

I wish we had an ETA on that

This is some excellent information, thank you! I set up a sliding rig for my camera right now and did a few test runs to adjust the settings, and hopefully tomorrow I’ll be able to get some decent images of the test. Does the test speed have any effect on the results? If so, what would be the ideal speed for Spectrum?


The ideal speed depends on your skill as a pursuit photographer and the rail’s stiffness (e.g. stiffness of wood blocks versus shakiness of tripods), as well as the smoothness of the ball bearings in the pursuit rail.

TL;DR Version:

  • 1080p mode at DPI100% are easier to pursuit camera at 960pps
  • 4K mode at DPI100% may need 1920pps to capture nuances better
  • Faster motion allows you to compare smaller blur differences
  • Slower motion is easier for hand-wave pursuit (rail-less) or rickety rails on cheap tripods.
  • Twice motion speed doubles motion blur for all pursuit photography, just like you’d see with your real eyes too. Smaller blur differencs are easier to compare with faster motion.
  • Prioritize on how accurate you can get with your manual pursuiting skills (rail based or handwave based)
  • Try to use live preview while burst shooting. Hold down shutter while pursuiting, or use your high-bitrate manual-settings-configurable video mode as a stand-in for burst shoot.

(Not all cameras have video good quality enough that a freezeframe is a viable pursuit photo)

The Long Story Version

Sometimes handheld wave cameras even exceed accuracy of a rail because the camera didn’t have live preview during burst-shoot. It’s much easier if you can watch the live preview while pursuiting (to allow you to see the ladder tilt/skew in realtime).

Take a look at slow UFOs at
Observe it’s harder to compare the motion blur of the 3 UFOs.

Take a look at faster UFOs at
Observe it’s easier to compare the motion blur of the 3 UFOs, but pursuiting faster will be a lot more challenging.

Your sweet spot pursuit speed is the fastest you can pursuit accurately, and typically that is very skill dependant, display resolution dependant, and what your goals are (comparing different strobe pulse widths needs faster motion, comparing 60Hz vs 144Hz can stay at 960pps)

So I cannot answer your question with boilerplate one-size-fits-all, but recommend 960pps for 1080p and 1920pps for 4K as an approximate baseline. The UFOs will be tiny at 4K so you will have to increase the live-preview zooming to get one UFO row + two sync tracks to fill the height of a landscape photo — while camera-vs-screen is about normal human viewing distance. Without getting the camera too close to the screen (closer is OK, but it can exaggerate viewing angle issues, as if a human is staring at the screen closer than normal), Now getting the camera closer to the screen may be easier earlier on the training process, especially if you’re stuck with digital zoom.

Faster speeds add more motion blur. Just like faster-moving UFOs have more motion blur. Double motion speed has twice the motion blur at the same MPRT.

This makes it easier to see tinier MPRT differences like 0.5ms MPRT versus 1.0ms MPRT (e.g. Strobe Pulse Width 5 versus Strobe Pulse Width 10 during 100Hz refresh rate. The Pulse Width is in percentages of refresh cycle, so you can calculate the approximate MPRT of your Eve Spectrum Strobe Backlight from the Pulse Width number).

The slower the motion in pixels per second, the harder it is to see MPRT differences, but it is easier to eye track.

The faster the motion in pixels per second, the easier it is to see MPRT differences, but it is harder to eye track.

A display’s “retina refresh rate” or “retina MPRT” from a motion blur perspective is simply thusly, dependant on a human’s fastest eye-tracking speed — usually about 3000 pixels per second at 1080p 30-degree FOV, and 6000 pixels per second at 4K 30-degree FOV.

VR headsets have wider FOV, so they have a higher retina refresh rate because you have more time to eye-track more pixels per second, in order to detect MPRT differences. That’s why Quest 2 and Valve Index are 0.3ms MPRT (that’d require 3333fps at 3333Hz to eliminate motion blur strobelessly).

It’s called the Vicious Cycle Effect — higher resolutions and wider FOV raises the retina MPRT (raises the non-strobed refresh rate, or shortens the minimum human-beneficable strobe pulse width). Retina MPRT is under 0.1ms, and retina refresh rate is above 10,000 Hz for a 180-degree FOV 16K VR headset. This is why refresh rates is fighting against resolutions for human visibility benefits.

The standard Blur Busters recommendation is to geometrically upgrade refreshrates for human-visible benefits to the mainstream — e.g. 60 → 120 → 240 → 480 → 960 (or 1000 Hz). Or even bigger steps, 60 → 144 → 360 → 960. Incrementalisms (144->240) doesn’t benefit as many mainstream people as esports people, so the everyday user should focus on ~2 to ~3x refresh rate upgrades to see human visible benefits, and stop laughing at 240Hz or 360Hz - even 360Hz is good for mere web browsing too (…clearer browser scrolling…).

Faster speeds (1920pps and faster) is needed for sub-1ms-MPRT photography, since 960pps only captures blur down to 1ms MPRT. But for 0.5ms MPRT versus 1.0ms MPRT, you want 1920pps photography, since that 0.5ms = 1 pixel of blur per 2000 piselx/sec, with the Blur Busters Law mathematics explained at Blur Busters Law: The Amazing Journey To Future 1000Hz Displays | Blur Busters

Blur Busters Law

1ms of persistence = 1 pixel of motion blur per 1000 pixels/sec motion

This is the simplified math formula of MPRT(100%). MPRT is frametime on non-strobed displays, and MPRT is flashtime on strobed displays. MPRT is just simply merely pixel visibility time.

Pixel visibility time is motion blur, just like a camera shutter.

Strobe backlights reduce motion blur — the backlight is essentially behaving as a remote shutter for the visibility of display motion blur. A 1/500sec flash (2ms MPRT) is the same motion blur of a SLR camera configured to a 1/500sec shutter speed. It would take 500fps @ 500 Hz to eliminate the need to have black time (shutter-closed) between frames, to have the same zero motion blur as an 2ms MPRT strobe backlight.

Which is why 1000fps @ 1000Hz is needed to do 1ms MPRT strobelessly (identical in motion blur to 1/1000sec camera shutter).

This is why TestUFO standardized on 960pps, as it’s the easiest number closest to 1000 that is divisible by common refresh rates (60 Hz, 120 Hz, 240 Hz):

HOWTO: Compare 0.5ms MPRT versus 1.0ms MPRT on Spectrum

  1. 4K at 100 Hertz refresh rate, with DPI 100%.
    100Hz = refreshtime of 10ms
    100fps = frametime of 10ms for VSYNC ON

This makes it easy to understand MPRT
10 pixels of motion blur for default TestUFO speed

BONUS: better if this is a QFT 100Hz, to reduce top/bottom strobe crosstalk, use the Quick Frame Transport HOWTO to create a reduced-strobe-crosstalk 10Hz mode: HOWTO: Quick Frame Transport (QFT) - Large Vertical Totals (reduce lag, reduce crosstalk) - Page 3 - Blur Busters Forums

  1. Turn on Backlight Strobing.
    Short = 5% refresh MPRT (0.5ms at 100Hz)
    Medium = 15% refresh MPRT (1.5ms at 100Hz)
    Long = 25% refresh MPRT (2.5ms at 100Hz)
    Custom = Adjustable from 1% to 25% refresh cycle MPRT, via Strobe Utility download at Blur Buster Eve Spectrum Strobe Tuning Completion - #36 by BlurBusters

  2. View TestUFO Panning Map Test at 3000 pixels/sec or faster
    TestUFO: Photo

Now you can see 0.5ms MPRT differences because at 3000 pixels per second, there is 3 pixels of motion blur at 1ms MPRT, making the tiny street label text blurry.

So you need to reduce MPRT to less than 0.5ms to read the street name labels!

100Hz makes MPRT math calculations easier, so you can predict how many pixels of motion blur you will be seeing even before you fire up TestUFO.

MPRT100% being perfectly accurate does depend on GtG=0, but fortunately good strobe tuning hides GtG pixel transitions away from human eyes — in the blanking interval of the OFF period of backlight between refresh cycles. So for Eve strobing, GtG is effectively hidden, making what you see pretty much pure MPRT motion blur — which often exactly follows Blur Busters Law. Knowing 4K 100Hz is exactly 10ms MPRT during non-strobed, and knowing exactly what MPRT is during the pulse width settings — now you can compare MPRT100% numbers. You’ve already learned by now, faster smooth jitter free motion means tinier MPRT differences are human visible. 4K-ness and better-than-60Hz-ness, means 0.5ms MPRT vs 1.0ms MPRT is as clear as bell on a Spectrum 4K144 during this specific demo.

Obviously, there’s a brigttness-versus-clarity tradeoff, since shorter pulse widths are darker.

Regardless, this is see-for-yourself proof that 1000fps 1000Hz isn’t even the retina refresh rate without needing strobing…. This is why we are stuck with backlight strobing as a display motion blur band-aid for the forseeable future.


Can we just take a second to appreciate the valuable and informative contributions Blurbusters makes to this forum. Always a lot of effort and thought put into their posts; and despite some of the technical verbiage going over my head, is a fascinating read :slight_smile:


A couple of questions ( #1,#2, #3 is for @BlurBusters and #4 and #5 is for @Javild )

  1. Would it be possible to enable Dynamic Overdrive using DDC commands on spectrum?
  2. Will it be possible to move the clarity? like if I wanted the backlight strobing clarity in the middle or top?
  3. Does the fact that this monitor have 12 edge lit local dimming zones help at all at doing something like a rolling shutter effect to create low crosstalk across the entire panel rather than just one part of it?
  4. I heard that the “KVM switch” is a manual effort where you have to manually specify if you want the upstream to be from the usb c or the usb B connection. Is there a DDC code that would allow us to write a piece of software so we have have a shortcut that will not only switch inputs for us but also switch usb upstream ports? ClickMonitorDDC is an example software that already exists that would allow users to write these shortcuts themselves and could prove useful as a template.
  5. Any plans on a OS side OSD application to control monitor functions through windows/linux desktop? With DDC commands this could prove useful.
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  1. Yes, that’s the intent (though that is a separate phase (project phase #4) that may happen after VRR strobing firmware update (project phase #2)
  2. Yes, that’s the intent (strobe pulse phase)
  3. That won’t help because of internal backlight diffusion, see technical explanations below.

Why Global-Strobe Backlights are Superior To Most Garbage Scanning Backlights

Theoretically, a scanning backlight is superior to a global strobe, because displays don’t refresh pixels simultaneously (see Understanding Display Scan-Out Lag With High Speed Video | Blur Busters …) so sequentially lighting up the backlight behind the LCD scanout, can in theory reduce strobe crosstalk.

But, then there’s reality.

We wrote about this as early as year 2012 back when Blur Busters was named ScanningBacklight(.com) for those who knows about Blur Busters ancient history.
Scanning Backlight FAQ | Blur Busters and Electronics Hacking: Creating a Strobe Backlight | Blur Busters … back in year 2012, we were scanningbacklight(.com) before we renamed to Blur Busters, so we definitely know the severe strobe-crosstalk limitations of scanning backlights caused by internal light difussion between ON-segment to the OFF-segment.

Global strobe backlights are usually vastly superior to scanning backlights until using a well-programmed approximately ~1000-2000+ zone backlight, due to internal light diffusion effects. (Unfortunately the hoped-for scanning ULMB did not arrive in G-SYNC Ultimate displays).

For a fully transparent LCD panel (e.g. all pixels white), the OFF segment should be completely totally dark, despite another part of the backlight being ON.

Unfortunately, in real world, the contrast ratio is usually only 5:1 or 10:1 for edgelights. A 10% light leakage between the ON segment to the OFF segment, creates a 10% strobe crosstalk in a scanning backlight.


To reduce strobe crosstalk to about 1%, we need a backlight-only contrast ratio of at least 100:1 for a solid white field (100 IRE), which is not possible with any current edgelight technology at all; it requires a dense FALD. Some implementations of scanning edgelights are fairly decent (e.g. Samsung CHG70 series). That scanning edgelight successfully gets clearer for top/bottom but worse for screen center.

But scanning edgelights have more overall ghosting/crosstalk effects than even the best global-strobed KSF panel like firmware V100R852 or newer of the Eve Spectrum 4K144. And even that can be fixed via hertz headroom + QFT large-VT mode, which almost unifies top/center/bottom clarity – global strobes is now able to reach zero crosstalk with the combination of hertz headroom + large VT techniques.

MiniLED “Knight In Shining Armour” Coming To Rescue Mediocre Scanning Backlights

Scanning backlights can be superior again, once MicroLED FALD becomes mature AND their controllers are flexible enough to be programmed to a microsecond precision per LED. Combining strobing and HDR would be the holy grail, with the nit headroom of HDR FALD’s to make strobing brighter. Especially if voltage boosting is also thrown in, for 1000-nit-peaked strobed HDR.

The sheer increase in LED count, shrinks the internal light diffusion between ON-vs-OFF segments, dramatically increasing the backlight-only contrast ratio. Beyond about ~2500 LEDs in a MiniLED backlight, strobe crosstalk of scanning backlight can become lower than global strobe, but the scanning zone may still need to be tight (requiring 8000nit voltage-boosted surges to average 1000nits).

But combining sub-refresh backlight control precision into a Full Array Local Dimming (FALD) is hard, which I am imagining/guessing (realistically) why G-SYNC Ultimate FALD displays did not have NVIDIA ULMB. A commodity FALD sheet can only be refreshed at a granularity too low for precision scanning-strobe.

Few people (except Blur Busters and a few others) knows how to spec-out a FALD backlight to be strobe compatible. Since the capability needs to be essentially baked into the hardware. It is not as simple as strobing a few LEDs, since you don’t have direct GPIO access to each individual LED individually, in a FALD backlight.

P.S. Blur Busters remain available for services to the monitor industry in perfecting a FALD HDR scanning-strobe MiniLED backlight – we got the technical know-how now.

And now for a status update on strobed VRR



Some interim Javid practice pursuits are posted at Looking for test performance feedback | Pursuit camera ghosting test on Eve Spectrum ES07D03 - Blur Busters Forums

He’ll post some further-improved pursuits – there’s a bit of a camera defocus & camera vibration issue at the moment.


Yep, I’m currently working on improving the shots, but meanwhile, here’s one of the more recent ones, shot on short pulse width at 4K@100Hz. I still need to improve the shots to accurately represent what you’d see with you eyes, but this gives you a decent idea of the performance.

Low Strobing Test 1

I don’t have new images yet, but with manual tuning, the performance looks even better.


Yes – that’s darn near zero strobe crosstalk (no ghost at left edge), with only the red-phosphor KSF ghosting on the right-edge. In real world, this is far less noticeable.

This is less visible than the yellow ghosting on plasma displays, but more visible than the green ghosting on CRT tubes – for bright objects on dark backgrounds.

You also chose the worst-case background (dark cyan) rather than the brighter cyan background that will hide more of the KSF ghosting better.


This is really impressive looking results. I hope VRR backlight strobing will look similar to this. I think it’s funny that sat the beginning of this project being announced I mentioned how adding proper backlight strobing would make this monitor something really special and introduced you guys to blur busters for their tuning :slight_smile: and look where we are now, with backlight strobing that looks superior to most gaming monitors out there and making this monitor something really special

It looks REALLY good and color me impressed. I can’t wait to see more pursuit photos