Chief Blur Buster wrote:
Notty_PT wrote:Why you want strobing at 60hz VS no strobing 144hz?
There are use cases.
Even Low-Hz strobing has less motion blur than even 240Hz.
Blur Buster's Law
"1ms of pixel visibility time (persistence) equals 1 pixel of motion blur per 1000 pixels/second"
(For more detailed math and animations, plus links to papers, see 1000Hz Journey
Non-strobed displays (where GtG isn't the limiting factor to the refresh rate)
60fps at 60Hz = 1/60sec motion blur ~= 16.7ms = 16.7 pixels of motion blur at 1000 pixels/sec
120fps at 120Hz = 1/120sec motion blur ~= 8.3ms = 8.3 pixels of motion blur at 1000 pixels/sec
240fps at 240Hz = 1/240sec motion blur ~= 4.2ms = 4.2 pixels of motion blur at 1000 pixels/sec
480fps at 480Hz = 1/480sec motion blur ~= 2.1ms = 2.1 pixels of motion blur at 1000 pixels/sec
Strobed displays, any refresh rate, as long as framerate equals refresh rate (e.g. VSYNC ON)
8ms flash per unique frame = 8 pixels of motion blur at 1000 pixels/sec
4ms flash per unique frame = 4 pixels of motion blur at 1000 pixels/sec
2ms flash per unique frame = 2 pixels of motion blur at 1000 pixels/sec
1ms flash per unique frame = 1 pixels of motion blur at 1000 pixels/sec
See.... You only need 1ms flash ULMB VSYNC ON perfect FPS=HZ, to match the motion clarity of a 1000Hz display*
(*with some caveats, read below)
As a result, strobed VSYNC ON is a much easier way to reach those "diminishing points of returns" than ultra refresh rates. It does have more stroboscopic effects, but motion clarity of TestUFO is exactly the same. Remember, persistence is pixel visibility time
, you can use shorter frames or do strobing to reduce pixel visibility time. The motion blur math is the same.
Strobe crosstalk (see FAQ
) gets worse at higher Hz, so lowering the refresh rate well below maximum can massively improve strobe quality. A compromise strobe frequency is approximately 85Hz or 100Hz. Not as flickery as 60Hz, but not as strobe-crosstalky at 240Hz.
That's why we sometimes like 1ms-flashed 60Hz strobed displays. Though 60Hz flickers quite a bit.
- Some of us have more eye pain from motion blur than eye pain from flicker.
- Vision sensitivity to various things vary a lot between humans.
- Some are sensitive to colors. Others are not (color blindness or partially)
- Some are sensitive to stutters. Others are not.
- Some are sensitive to tearing. Others are not.
- Some are sensitive to motion. Others are not (motion blindness called "Akinetopsia", but partial cases exist too)
- Some are sensitive to flicker (PWM, CRT, strobe, or only some kinds of flicker, etc). Others are not.
- Some can see perfectly clear better than 20/20. Others are not.
Everybody tends to see slightly differently than the next human.
So if flicker is unimportant, 60Hz blur reduction (e.g. BenQ XL2411P) is sometimes a godsend for those 60fps-locked games or gaming consoles.
Sure, some of these are first world problems, but in the age of PWM-free monitors with GSYNC/ULMB, few monitors are properly targeted to the blur-sensitive. And the mantra of "use VSYNC OFF" does degrade strobe quality somewhat (kills the TestUFO-smooth effect) since framerate-locked motion has less eye-pain when you use strobed modes.
VSYNC OFF is great for low lag. But when using ULMB with refresh-rate unsynchronized motion....uhhhh, excuse me: Fluctuating low-framerate with strobe backlights can create eye pain during strobed operation for some people due to the serrating effect of random multi-image effect, it's like a serrated knife for certain human eyes:
Some people can't stand that, it creates major eye pain (moreso from this artifact THAN from the flicker!) Sometimes flicker is the problem. But we have readers here who get eye-pain from PWM but no pain from ULMB VSYNC ON. So, to fix the problem, you need to lower strobe rate to the same ballpark of the framerate....or preferably perfect match.
Not everybody is bothered by it. But some of us are; the eyestrain disappears for some of us with perfect framerate-matched ULMB.
- Some of us can tolerate global flash (varying average photons like ULMB)
Pretty fine with ULMB
- Some of us can only tolerate rolling scan flicker (constant average brightness; some dot is always illuminated)
Only motion blur reduction we're comfortable with is CRT
- Some of us are flicker sensitive of any kind (all pixels must stay continually illuminated)
These people flickerfree LCDs, PWM-free, with ULMB turned off
- Some of us are painfully stutter sensitive to the point where stutter is nausea
These people find VRR, FreeSync, GSYNC a godsend.
- Some of us are sensitive to the artifacts of flicker (can't stand motion artifacts like double-images)
People who get eye pain from PWM-dimming but no eye-pain from strobing VSYNC ON ULMB
- Varying combinations of above sensitivities.
e.g. eye pain from PWM-dimming and eye pain from ULMB until ULMB reaches 144Hz.
e.g. eye pain from stutters AND blur. Requiring perfect stutterless framerate-locked VSYNC ON ULMB
e.g. eye pain from stutters AND blur AND flicker. Requiring ultra-Hz to fix.
Or other vision-sensitivity combination
Thousands of people. Being the only website in the world, people reach out to me asking questions privately, email, PM, DM, etc. While I tell them to post publicly, sometimes they are desparate and I try to give them the best advice I can sometimes.
Blur Busters has many dozens of cases of EACH category above. Some of it is poorly scientifically studied, but some of the scientific links are also in the lighting industry paper linked from the 1000Hz-Journey
If any researcher reading this, I'm willing to fund a peer reviewed study about "motion blur eyestrain" and the varying thresholds of "flicker discomfort" ratio to "motion blur discomfort" that I've experienced hundreds of people with, ever since Blur Busters launched in Year 2012.
Now, keeping this in mind:
--> Respect People's Preferences From Vision Sensitivities <--
No feeding words in other people's mouths, everyone has preferences.
Myth: "Everyone will always hate 60Hz strobe, its useless to everyone" <-- discouraged on Blur Busters
Myth: "You should never bother with ULMB, it's stuttery/jittery" <-- discouraged on Blur Busters
Myth: "VSYNC ON is useless for everything" <-- discouraged on Blur Busters
Myth: "VSYNC OFF is useless for everything" <-- discouraged on Blur Busters
We all have our own preferences!
So, back to low-Hz strobing.
It doesn't help everyone, but some guidelines to make low-Hz strobing better:
1. Sit slightly further away. Modern computer monitors are bigger than CRT screens.
2. Reduce screen brightness or play games with dark backgrounds. LCDs are brighter than CRT.
3. Adjust ambient lighting.
4. Take breaks.
Then it's the lesser poison of "pick-poison" vision problems sometimes. Sure, some of us have to bump to 85Hz ULMB instead of the 60Hz ULMB Hack. Or we're perfectly fine with 60Hz strobing. It's annoying when NVIDIA disallows 60Hz ULMB when some manufacturers enable it. Some manufacturers just simply display a warning message "WARNING: Flicker. Discontinue using if you have headaches [...] yadda yadda" and that's good enough. Some of us need 60Hz strobing.
So, now, there's side effects of low-Hz strobing.
1. Stationary Gaze Issue While Motion Scroll Past: Stroboscopic artifacts
While motion blur is fixed, the stroboscopic effects aren't fixed. The lower the Hz, the more gapped motion is (e.g. steppy or dotty motion in games with high contrast stuff), regardless of whether you do strobing or not.
2. Duplicate images during eye tracking if framerate not matched with refresh rate
That's why strobing often does not look good if frame rate diverges from strobe rate. This is the side effect caused by framerate (not strobe crosstalk caused by pixel response limitations). Same old fashioned CRT/plasma 30fps at 60Hz issue, the old double-image rule occurs when running framerate that is half strobe rate (e.g. 60fps at 120Hz ULMB).
But, if stroboscopic artifacts are no problem, and you're not flicker sensitive....Then...Well, 60Hz strobing is a godsend.
Certainly the strobe lag is a problem for competitive sports but some of us love to play scrolly RTS games that looks amazing with ULMB. With perfect-clear Nintendo-smooth Sega-arcade-smooth TestUFO-smooth ULMB in those scrolly games like RTS or Sonic Hedgehog platformers or if we're an "eye-tracker instead of a crosshairs-starer" in certain turny/scrolly/panny games that have no fixed points of references like a crosshairs. For the non-flicker-sensitive person, 60Hz ULMB hack (or ULMB+GSYNC hack with the RTSS 60fps cap) can be a godsend for emulator use, and look better than software-based black frame insertion.
Low Hz Strobing Can Be Useful Tool
TL;DR Using low-Hz strobing can be a shortcut to motion nirvana than ultra-Hz, if you don't mind flicker or stroboscopic artifacts. You simply lower the strobe refresh rate to just above your flicker tolerance threshold. Then it's much easier to get "framerate = refreshrate = stroberate" with your GPU.
Unfortunately, the only way to solve flicker+stroboscopic artifacts simultaneously with fixing motion blur, will be the ultra-Hz technique of motion blur elimination, instead of the strobe-based technique of motion blur reduction..
However, Refresh Rate Race Must Go On, As One-Size Fixes All
--> 1000fps@1000Hz = No blur, no flicker, no stroboscopics, no stutter, no tearing, no motion artifacts, all gone simultaneously
--> 1000fps@1000Hz = merges all the advantges of VSYNC ON / VSYNC OFF / ULMB / VRR / GSYNC / FreeSync simultaneously into one
--> Even as games catch up, as well as Frame Rate Amplification Techonologies / Framepacing Technologies needing to catch up.
--> New readers: Want to read more about the refresh rate race?
Then read this amazing piece: Blur Busters Law And The Amazing Journey To Future 1000Hz Displays