The S3D Centre at the Emily Carr University of Art+Design has posted a whitepaper containing the results and conclusions of its research into high frame rates and variable frame rates:
Download An exploration into the creation of variable frame rate (VFR) stereoscopic 3D narrative productions [interactive, 2.8MB PDF] | [print, 5.4MB PDF]
The paper – which presents their findings regarding HFR/VFR pre-production, production, and post-production – is based on the S3D Centre’s experience last August directing “L’âme Soeur (Soul Mate) 3D”, the “first variable rate HFR shoot of its kind” as a combination short film / research project.
Researchers found that it was difficult to go back to standard frame rate footage after being treated to the extra detail of the HFR version:
While watching the SFR version of the material if felt that visual information was missing. Additionally, imperfect movements whether a shaky moving shot or jerky dance move became even more pronounced in HFR S3D. To counter this, the 23.98fps version of the clip used its blurred frames to ‘smooth’ the image compared to the HFR versions.
Similarly the dancer in the short film was a very beautiful dancer but sometimes the HFR created a kind of ‘animated’ look to her dancing. 23.98fps seemed to retain the ‘soft, graceful’ aesthetic of dance, but it also enhanced blur and judder to the point that it was unwatchable in 23.98fps. Lighting on a human subject appeared more defined in HFR, and when viewers of the material suggested it made a person look video-game like, it can be speculated that this sharper lighting was the reason. We had used fog machines to soften the lighting, so this appears to be a genuine HFR concern.
They observed that close-up shots were much more intimate (perhaps too intimate) in HFR, and that the perceived detail of background elements increased dramatically:
The HFR handheld shots were shockingly intimate, and could be intercut among different moments to create unique effects. Likewise HFR close ups of faces often broke the tolerable intimacy boundary for the viewer. It can be considered that this observation can be a strength, or major distraction depending on the focus of the story. All researchers observed that the background separated and was more defined in the HFR versions than in 23.98fps within the film. This is an advantage for S3D, but it should be noted that caution with set decoration must be taken. Any flaws in the background become more pronounced in HFR.
Overall, they found that the choice of HFR/VFR vs. SFR depends on the emotion(s) the filmmaker wants to elicit in the audience:
Early results with the variable frame rates of 24, 48 and 60 fps have shown that the emotional impact of static shots far exceeds what was originally expected for the viewers, and dynamic shots still suffer from motion artifacts that are actually caused by the HFR. A comparison of the VFR/HFR and SFR version of “Soul Mate 3D” show that VFR is indeed a valuable flexible tool dependent on the content of the narrative.
I’m curious about the video-game / animated-looking motion artifacts in dynamic shots that they claim are caused by the fact that lighting looks sharper and more defined in HFR. I understand that HFR will accentuate jerky / shaky movements of the subject, but I don’t quite understand what they mean by this concern (alas, all I’ve seen of HFR is The Hobbit and a number of amateur videos).
I hope the S3D Centre posts some of their conclusions regarding the granular application of differing frame rate to various objects within a scene (from what I’ve heard the next Hobbit movie will do this).
There is further interesting discussion of the emotional impact of various utilizations of HFR and VFR in their 4th Blog Post.
Check out all of the S3D Centre’s previous HFR Film Blog entries:
HFR Film Blog #1 ”Introduction and Creating a HFR Film” (September 13th 2012)
HFR Film Blog #2 “Effective Pre-Production and Production” Part 1 (November 8th 2012)
HFR Film Blog #2 “Effective Pre-Production and Production” Part 2 (November 21st 2012)
HFR Film Blog #3 “Effective Post Production and Dailies Pipelines” Part 1 (December 8th 2012)
HFR Film Blog #4 “Discussing HFR Technology and Standards” (coming April 2013)
Visit S3D Centre’s HFR (High Frame Rate) Research Home Page
Visit the S3D Centre’s Vimeo page for a video summarizing their HFR/VFR S3D research, 24 fps vs HFR comparison footage and a behind the scenes video of the “L’âme Soeur (Soul Mate) 3D” shoot.