Cinematography of 2030s: Ultra HFR! I have witnessed realtime 1000fps on real 1000Hz.
Interesting reading of future Ultra-HFR.
Mark Rejhon wrote:Hello,
I'm the founder of Blur Busters -- and author of TestUFO Motion Tests. I consider myself an expert in displays and of low-persistence. I'm the co-author (along with NIST.gov, NOKIA, Keltek) of a peer reviewed conference paper on a display motion-blur testing technique, and am also the world's first mainstream reviewer to test a true-480Hz display and have also seen 1000Hz+ displays in the laboratory now. I have consequently written Blur Busters Law: The Amazing Journey To Future 1000 Hz Displays. I am more well known by gaming monitor manufacturers and eSports players, but since Blur Busters is slowly expanding news coverage into HFR (120fps, and even true-240fps+) content. I'm also a invited guest moderators of /r/hfr on Reddit now. I have had a few contracts with gaming monitor manufacturers to reduce display motion blur.
I'm one of the few people in the world to be able to do a good "Plain English" job of explaining display persistence (causes of display motion blur), which is explained in the 1000 Hz article. I'm the inventor of several optical illusions that is intentionally generated by display motion blur: TestUFO Eye Tracking and TestUFO Persistence Of Vision.
Also, resulting motion blur (seen by the human eye) is the sum of the source persistence (camera shutter length) and destination display persistence (pixel visibility time).
Meaning, a camera with 1/300sec shutter speed, displayed on a sample-and-hold display of 1/60sec frame visibility time, creates (1/300sec + 1/60sec) = (6/300sec) = 1/50sec of motion blurring for on-screen moving objects. A film that is filmed with a camera of 1/120sec shutter displayed on a 24Hz flickerfree DLP (E-Cinema), creates (1/120sec + 1/24sec) = (1/120sec + 5/120sec) = 1/20sec of motion blurring. (Assumption is frame rate matching refresh rate, of course -- there are many variables -- but once you've got a match, the mathematics is simple.)
Display Persistence is the destination-side equivalent of the camera shutter -- it is also known as MPRT (Moving Picture Response Time) in scientific papers) -- and reducing persistence is usually done via flicker (strobing, BFI, CRT impulsing, etc) but can also be done via a higher frame rate. At the end of the day, display motion blur is linearly proportional to pixel visibility time, and it's easily demonstrated in the motion test links above, and already well-documented by papers well outside the filming industry. Virtual reality needed to reduce motion blur because motion blur causes nausea (extra blur above-and-beyond natural human vision limits) in a Holodeck-like environment, so intense research is occuring to eliminate blur (both source-side and destination-side). Now, today, I am increasingly crossing-over between the source-side equation and the destination-side equation. And HFR cinematography, sometimes reaches into virtual reality (360 degrees). So my writings is slowly increasing into HFR too.
Intentional motion blurring is often added to frames to prevent stroboscopic and wagonwheel effects. Unfortuantely, adding camera blur or artifical blur is also a cause of nausea for some in virtual reality (VR). So you need to eliminate both motion blur and stroboscopic effects. The only way to do both simultaneously (can't add blur, can't have stroboscopic effect) is keep raising frame rates. That means things like true 1000fps at true 1000Hz. VR scientists have now agreed that going to at least quadruple-digit framerates, is necessary to pass a Holodeck Turing Test (unable to tell apart VR from real life). We still even get stroboscopic effects even on my true-480Hz display. While resolutions have gone Retina, true genuine frame rates + refresh rates are very far away from reaching Retina (e.g. achieving high enough framerates & Hz that it's not necessary to add motion blur to individual frames) by more than an order of magnitude.
From my true-480Hz tests:
(One of the several artifacts forced by refresh rate granularity)
Early canary tests show promise in ultra-HFR video (e.g. true realtime 1000fps video!) which are successfully simultaneously blurless & stroboscopicless. This is a distant vision of what is to come (~2050) especially if 1000fps / 1000Hz becomes cheap. Today, in the lab with actual displays, it's much easier to tell apart [email protected] and [email protected] than it is to tell apart 4K and 8K. I love 8K as much as all of you, but it is surprising of the little focus on providing cinematographers further additional options. It can be increasingly important (e.g. blurfree+strobefree 360 degree videos for VR) to avoid viewer nausea for a bigger-sigma percentage of human population. Currently, VR headsets use 90Hz pulsing, but future VR is expected to go even further in frame rates in the decades to come to reduce the need for strobing/flicker as the blur-reduction technique, and migrate to sheer framerates as the blur-reduction technique. Research is also being done on frame rate amplification technologies for video games (Oculus can convert 45fps to 90fps laglessly, in a 3D-aware manner, without rerendering the intermediate frames) and tomorrow's tech may convert 100fps to 1000fps with less need of full re-renders between frames -- due to anything different from real life (e.g. flicker, blur, stroboscopic, etc) causing nausea in virtual reality environments. But this is also human-visible on a stationary display too, including experimental displays too, so the VR innovations may spinoff to future ultra-HFR.
Nobody talks about it yet, but what we see in the lab, means 120fps HFR is not the final frontier when we predict outwards to 2030s-2040s, we see ultra-HFR now becoming a more mainstream topic (then) within our lifetimes given the incredible rapidity of VR innovations occuring (and actually feasting my eyes on real 480Hz+ and 1000Hz+ laboratory displays myself -- essentially flickerless and strobeless with uncannily CRT-quality motion with zero stepping artifacts). After resolutions have maxed out to Retina leagues, we now believe frame rates and refresh rates is one of the new racees that will continue outwards to the end of the 21st century, especially with the mother-of-necessity VR pushes.
Motion blur is lovely when we want it. It is very cinematic. But sometime, certain situations, we want to understand how to control it & eliminate it. Since virtual reality often requires elimination of motion blur to prevent motion sickness (avoid extra blur forced on eyes, above-and-beyond human vision) -- the well known VR sickness. Now technology is arriving that makes this increasingly easier, for those specific kinds of situations where the Director's Intent is minimum-possible motion blur, or at least a fuller understanding of controlling motion blur via understanding source/destination-side in a deeper way.
I'm about to write a simplified HFR article on how source persistence and destination persistence combines into a final amount of perceived display motion blur. This article is of extreme great interest to 120fps HFR videographers who are trying to figure out how predict resulting motion blur that viewers will see, in order to best present their HFR material (Especially when they are allowed to choose a specific display for their HFR presentation). I'm the display-side expert, but with a good understanding of the interactions with source-side (camera blur) so this subject is a crossover for me. I'm now reaching out to a few HFR experts.
My questions to readers are as follows:
(1) Has there been any recent innovations in Ultra HFR? Video of frame rates above 120fps outside the laboratory, played realtime, not slomo?
e.g. Presentation of true-240fps video (non-slomo) on now currently-shipping true-240Hz eSports gaming monitors (more than one dozen models are now on the market).
(2) Are there any pre-existing articles in the HFR community, that accurately explain in a simple way:
e.g. How source persistence & destination persistence interact to create, a final human perceived display motion blur.
I am researching this, before I write about this.
I'd be happy to team-up with a known source-side expert (e.g. HFR expert) if you want to help me coauthor a flagship motion blur article for the HFR community worldwide.