May / 2012

Behind the Scenes with
Stereographer Brent Robinson

by Fanen Chiahemen

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Recent years have seen a spike in 3D filmmaking in this part of the world, and by all accounts 3D shooting will eventually be all but the norm (see “3D is Here to Stay,” Canadian Cinematographer, January 2011). Increasingly, the cinematographer is working alongside the stereographer, who some may say is the first line in the 3D-making process.

Toronto-based stereographer Brent Robinson, who most recently worked on the thriller Nurse 3D and the upcoming documentary Storm City 3D, explains that as a stereographer he is “responsible for the composition of depth and making sure the 3D lends itself to the narrative.” He adds, “I try to help bring what the director and the DP have in mind for a shot and accommodate the 3D to the mise-en-scène.”

3D shooting requires two cameras, Robinson explains. “One camera shoots what the left eye sees, and the other camera shoots what the right eye sees. It’s as simple as that. And where they both point together and intersect, that’s your convergence point. If you place your convergence point close, everything behind the convergence point falls deeper into the screen. And as you push your convergence point deeper, or diverge basically, things in front of that point come out of the screen,” he says. Interocular distance is the relative distance between the two camera eyes. The trick, according to Robinson, is to manage what is close and what is far in order to give optimal depth cues but not detract from the narrative.

There are many aspects to ensuring the best 3D shot is achieved, including matching lenses, aligning “eyes,” maintaining depth continuity between shots, cameras and units, and selecting effective camera positions and lighting. There are also a number of things that can complicate a 3D image, namely the differences between each eye in reflections, polarization, framing, bokeh (the quality of the blurred image), focus, camera sync and capture, field of view, and lens orientation. Robinson tries to manage those differences with live adjustments both electronically and mechanically.

One of the stereographer’s first tasks on a project is to lay out some depth cues and negative parallax notes in the script and boards with the director and cinematographer, Robinson says. For Storm City, the broadcaster Sky 3D provided a file with a technical breakdown of the desired 3D specs, according to director of photography Jeremy Benning csc. “Our goal with Brent was to do as much as we could in the camera, to make the 3D as accurate and well-aligned as possible, so there’d be the least amount of post work to correct anything optically,” Benning explains.

Robinson says in pre-production he is focused on script, storyboards, tech surveys, the camera package, and camera tests. “I can usually at that point start making suggestions. If you’re doing an action or a horror movie and something’s supposed to come out of the screen, there are certain ways that are better to expedite that than others,” he says. “For example, sometimes there’s a debate about what can fit out of the screen. A lamppost going straight up through the frame can’t come out of the screen, as your brain sees it behind the proscenium too, but certainly a tree branch or someone’s arm or an object flying toward the camera in a 3D moment, like arrows, can come out of the screen,” he adds.

" Stereographer Brent Robinson at work on A Park for All Seasons: Gwaii Haanas National Park, a 3D documentary for Oasis HD. Photo Credit: Diane Woods

Robinson therefore relies on good communication with the director of photography to determine how he can achieve the 3D alongside the DOP’s vision. In some cases that means an adjustment of the lighting plan, as Benning illustrates with an example from Storm City: “We had initially thought about lighting one of our sets with bare fluorescent tubes hanging in the shot, and that was something the director was really interested in doing. We did a bunch of testing in advance, and one thing we realized is that high contrast light is not good because you end up getting ghosting, and that’s due to the mirror and also the 3D system that you have wearing the glasses, and the way the image is displayed later. So we actually adapted our approach to that because we realized we couldn’t use bare light bulbs. It would just look terrible.

“Brent was very progressive in that he didn’t restrict that much,” Benning adds. “He said, ‘If you want to make something dark and moody, go dark and moody. If you want to make it bright, make it bright. But if you’re doing it dark, for example, try not to go so dark that there’s no connection between the foreground and the background, like a big pool of black where there’s nothing between the closest thing and the furthest thing.”

What’s most important is to make the 3D images “optimal yet comfortable,” Robinson says, explaining that the cameras for each eye “do have to match so when a viewer’s watching the film, it isn’t giving two different perspectives and straining your eyes and brain to make it work together. You have to have an alignment match between the two eyes as well as having it separated enough to show the depth in the scene. If you can take your 3D glasses off and still see what’s going on in the picture then it’s not terribly 3D. However, if you have so much separation that things are uncomfortable or you just get pain after watching a two-hour film, that’s not good 3D. I try to find a comfort zone that’s going to show the separation and the depths, but not strain your eyes.”

Not surprisingly, one of Robinson’s most important tools on a set are his 3D glasses. He also uses the app KeyFrame Camera Report to take notes on the set that he can then share with others. “I got the developer to collaborate with me to make it more suitable for my stereographic notations and make it more collaborative,” he says. “The notations are published online on a secure website on which all my shows reside, and then securely registered people – like the editor, the lab, and people above the line, and the visual effects company – they can just grab those notes, and there are pictures and detailed information. The great thing with metadata in the digital age is it really helps disseminate information down the pipeline.”

Robinson’s role doesn’t necessarily end once shooting wraps, as stereographers often work with visual effects artists and digital intermediate artists on the overall stereography, much in the same way that a DOP works with a colourist to fine-tune the final images. “I think it’s a good idea to be there in post to maintain the integrity of the 3D and ensure the stereographic notes have made it down the pipeline,” Robinson states. “I’m focused on keeping that continuity from shot to shot, from camera to camera, from unit to unit.”

Robinson has no formal 3D training, but he had been in the camera department for more than 20 years when he got into the role of stereographer by chance. “I owe a lot of this to [first AC] Mark Cyre, who I worked with on Scott Pilgrim vs. the World. He asked me to come on to Resident Evil: Afterlife [shot by Glen MacPherson csc, ASC] – which was in 3D – as a convergence puller,” Robinson recalls. “I thought it’d be an interesting job to learn, operating one eye of the camera and planning the depth of a shot. I was sort of thrown into the fire on that project and provided some additional stereo supervision.” Robinson says that opportunity has led him to a fulfilling position. His other credits include Silent Hill: Revelation and Bollywood's first S3D feature Haunted, which The Times of India in March called “the highest grossing Hindi horror film.”

“I like that it’s so technical and so creative at the same time. I’m not losing one in favour of the other one,” Robinson muses. “I have an opportunity to contribute to the viewers’ experience. It's very gratifying.”

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