Camera blur & display blur is additive. UltraHFR fixes this.

Discussion about 120fps HFR as well as future Ultra HFR (240fps, 480fps and 1000fps) playing back in real time on high refresh rate displays. See Ultra HFR HOWTO for bleeding edge experimentation.
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Camera blur & display blur is additive. UltraHFR fixes this.

Post by Chief Blur Buster » 12 Jun 2020, 01:51

Many videographers don't always realise this -- but, here is a new excerpt from the newly updated UltraFHR article (1000fps realtime video on 1000Hz displays).

Source Camera Blur and Destination Display Blur is Additive

A camera shutter 1/60sec combined with common display 1/60sec persistence = creates 2/60sec worth of motion blur. That's 1/30sec of motion blurring seen by human eyes when playing 60fps video taken with 1/60sec shutter, played onto a 60Hz sample-and-hold display! This is even assuming instant pixel response GtG 0ms, otherwise, there's worse motion blur than 1/30sec!

To reduce camera-side motion blur massively, a content creator can use a fast sports shutter 1/1000sec on the camera. But this will always be bottlenecked by destination display blur, from the sample-and-hold effect.

This diagram below is from our Pixel Response FAQ, GtG versus MPRT (the two different pixel response benchmarks). Flickerfree displays (sample-and-hold displays such as LCDs, OLEDs, MicroLEDs) produces a mandatory guaranteed added display-side motion blur:


To see this for yourself, we have TestUFO motion animations that demonstrates enforced motion blur caused by display persistence: TestUFO animation demo #1, TestUFO animation demo #2. As a general rule of thumb, the refresh rate of a flickerfree display is typically the guaranteed minimum display motion blur: 120Hz = 1/120sec = 8.3ms of motion blur = 8.3 pixels of blurring per 1000 pixels/sec motion.

To eliminate all motion blur weak links, both source shutter (1/1000sec) and display persistence (1ms MPRT) should be fast. There are two ways to reduce display motion blur:

1. Shorten display's frame visibility time via impulsing (CRT, plasma, black frames, etc)
2. Shorten display's frame visibility time via higher frame rate

The problem with approach (1) is you can produce stroboscopic stepping effects (phantom arrays) for fast-camera-shutter material such as sports, see The Stroboscopic Effect of Finite Frame Rate Displays. Besides, real life doesn't flicker or strobe, so impulsing is a humankind band-aid for simulating reality.

Solving motion blur and stroboscopic effect simultaneously requires ultra high frame rates: 1000fps at 1000Hz! One can do a 360-degree camera shutter blurlessly. A full-open shutter is only 1 millisecond during 1000fps video. A 1000Hz display is blurless sample-and-hold via sheer brute Hz.

This makes video look closer to real life, closer to a Holodeck -- with no framerate-induced limitations like forced motionblur or forced stroboscopic effects. This can make 1000fps UltraHFR less nauseating than 120fps HFR.


Being the founder of Blur Busters (Mark Rejhon), I used to work with video processor companies (RUNCO, Key Digital, and a PCI card containing a Faroudja chip). I was the author of the world’s first open source 3:2 pulldown deinterlacer algorithm twenty years ago in dScaler (Year 2000, Internet Archive).
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       To support Blur Busters:
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       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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