Can this Blur Busters chart be updated to show 30 FPS on a 60Hz display?

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willrs
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Can this Blur Busters chart be updated to show 30 FPS on a 60Hz display?

Post by willrs » 17 Nov 2021, 20:00

Blur Busters has this excellent chart showing blur for different FPS on different refresh rate displays, but it doesn't show 30 FPS on a 60Hz display, which is an extremely common combination, it would be great to see what that looks like compared to the others for reference purposes. Please add that to this chart! Here is the chart I'm talking about https://blurbusters.com/wp-content/uplo ... splays.png

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Re: Can this Blur Busters chart be updated to show 30 FPS on a 60Hz display?

Post by Chief Blur Buster » 18 Nov 2021, 21:49

One big problem about this is that 30fps is a little too low in the stutter-to-blur continuum. 30fps looks more like stutter to many people than motion blur.

You can see the stutter-to-blur continuum with this animation: www.testufo.com/eyetracking#speed=-1
Or in VRR frame rate ramping animations like www.testufo.com/vrr

Look at the bottom UFO for a minute, and observe how stutters blend into motion blur when the frame rate increases high enough, and goes down. 30fps is low enough to look like stutter instead of persistence-blur.

Thus, it will confuse too many users if I use frame rates lower than approximate flicker-fusion thresholds (the approximate region where stutters begin to blend into motion blur, like a fast-vibrating music instrument string).

So I prefer to keep it 60 and up, for simplicity.

However, a separate chart about blur-widths and stutter-widths can also be published eventually -- not everyone is familiar with the stutter-to-blur continuum.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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willrs
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Joined: 04 Nov 2021, 18:12

Re: Can this Blur Busters chart be updated to show 30 FPS on a 60Hz display?

Post by willrs » 18 Nov 2021, 22:42

Thank you so much for your response! This is really fascinating. And please do publish that separate chart about blur-widths and stutter-widths! I wasn't really aware of the stutter-to-blur continuum, and I'm surprised to learn that 30 FPS is below that threshold.

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Re: Can this Blur Busters chart be updated to show 30 FPS on a 60Hz display?

Post by Chief Blur Buster » 24 Nov 2021, 00:26

Motion Threshold -- Approximately 7-13Hz. This is when things stop being a slideshow and looks like motion.
willrs wrote:
18 Nov 2021, 22:42
Thank you so much for your response! This is really fascinating. And please do publish that separate chart about blur-widths and stutter-widths! I wasn't really aware of the stutter-to-blur continuum, and I'm surprised to learn that 30 FPS is below that threshold.
The stutter-to-blur continuum is a pretty fuzzy area.

There's many motion thresholds, cited by various research.
  • Motion Threshold -- Approximately 7-13Hz. This is when things stop being a slideshow and looks like motion.
  • Flicker Threshold -- Approximately 60Hz. This is when things stop looks like they are flickering when staring at it direct. The threshold is much higher (e.g. >100Hz) for peripheral vision, and lower (<50Hz) for darker softer strobing such as movie theatre.
  • Motion Blur Threshold -- Approximately ~1000Hz to ~4000Hz for a 24" desktop display. This is when motion blur completely disappears without needing strobing (aka low persistence sample and hold). 1ms MPRT requires 1000fps 1000Hz without strobing. The threshold can be much higher, such as 10,000Hz in extreme cases though, as per Vicious Cycle Effect near bottom of www.blurbusters.com/1000hz-journey
  • Stroboscopic Threshold -- Approximately 20,000Hz. Extreme tests can go beyond this, but the lighting industry has scientifically tested this. More information about this is found at www.blurbusters.com/stroboscopics
They are not exact threshold and can vary from human to human, but the "perfect display" with zero weak links need to solve all the above thresholds to look like a perfect Holodeck (looking through a window even for fast motion). It's surprising that even current triple digit refresh rates are still woefully imperfect for simulating analog real-life motion.

Eventually one of us needs to aggregate a lot of existing academic research that mentions these thresholds, but generally speaking, many people make the incorrect assumption if one threshold is met, the other thresholds don't matter.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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