SmallGantics - Bent Image Lab

SMALLGANTICS™
"Creating miniature DOF on full-scale moving footage"

by

Jim Clark

Earlier this year I was introduced to the captivating aerial photography of Olivo Barbieri via a web link sent by a fellow director at BENT. Many of us at the studio were fascinated with the technique and wondered how it might be achieved in motion. I took it upon myself to discover a process that would accurately recreate the images I saw as a child flying aboard jets: tiny streets, buildings, trees and vehicles. This is how I had seen the world from the air, as a miniature, and Barbieri's images made me want to see more. The part I wanted to figure out was how to do this with moving footage...

Early still image test with eight planes of DOF.

To get started, I began with a simple fake, creating masks in Photoshop and blur regions of the image to appear as miniature. The images had potential, but lacked the realism that true macro photography presents to the eye. It soon became clear that even the great images that Barbieri had created were not using true depth of field, but rather achieved through tilt-shift lenses. Unlike the narrow depth of field possible with telephoto and macro lenses, the tilt -shift technique does not create true DOF. Instead it positions the lens off angle to the back plane of the camera, blurring the top and bottom, or left and right side of the image. It doesn't actually create shallow depth of field. It tricks the eye into seeing a real landscape as miniature through what appears to be macro DOF, but certain objects in the frame can betray the illusion. For example, a telephone pole extending vertically from the bottom to the top of frame would start in soft focus at the bottom, shift to sharp focus in the middle, and return to soft focus on the top. In actuality, since the telephone pole is at a single plane in space, the amount of focus should remain constant.

Early still image test with fake DOF.

Tilt-shift is a clever approach, but I wanted to find a way to capture even more of the subtle complexities of true DOF. Moving imagery, especially a moving helicopter shot, presented some issues with a swing-tilt lens.

Still image test with eight planes of DOF.

We have coined our process 'Smallgantics'. Because of non-disclosure and proprietary reasons, I cannot disclose our exact technique, but I can explain the many issues posed. After a lot of experimentation and many failed approaches, we were ready to apply the technique to the right project. Soon after I was offered the great opportunity to oversee the creation of Smallgantics sequences for the Thom Yorke video "Harrowdown Hill" by Bent Image Lab's co-owner/director, Chel White. Visual effects artist Jalal Jemison was brought on to help lead the Smallgantics team.

Early still image test with eight planes of DOF.

So it happened fast, Bent was awarded the project and the team had only 3 weeks to deliver the completed video. Bent's Senior Producer, Tsui Ling Toomer, was responsible for the scheduling of the project and her hands were full, wrangling the tight deadline. Along with the 8 Smallgantics shots, the music video also contained stock footage treated with a glass pass technique developed by White, eagle animation by David Russo, live underwater footage of Yorke shot in LA at 150fps, and beautiful motion controlled time-lapse footage by long time Bent DP Mark Eifert. All in all, Bent delivered more than 4 minutes of original and treated stock footage in under a month.

Early still image test with ten planes of DOF.

To better understand the issues involved with the Smallgantic challenge, our team had to first consider the footage that needed treatment. We soon discovered that every shot would require a unique approach, depending on foreground elements, camera angles and scene complexity. We also concluded at this point that moving footage would be much harder to Smallganticize than we had anticipated. In the end, 8 Smallgantic shots were accomplished by a team of 6 full time compositers over a grueling 3 week period, and to make the task more difficult, we chose to complete the project in full HD resolution for future delivery potential.

Early still image test with five planes of DOF

The biggest challenge we faced for Harrowdown Hill was separating the depth of field planes that occur in the real world, which would allow Chel and the team to have total DOF control. Basically, we needed to present ourselves with the ability to pull focus through each shot and set the front and back focus at will. To say the least, it was a challenge and required many proprietary processes and software to make it work. It also took a lot of hand work from the talented team at Bent to pull off such a monumental feat.

Early still image test with two planes of DOF

Final frame from Harrowdown Hill

Web Links:
Thom Yorke music video - "Harrowdown Hill": LINK
Bent Image Lab: LINK
Chel White site: LINK
Jim Clark blog: LINK