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3D Natural History Filming

Mark Payne-Gill's 3D filming experience while shooting peregrines in 2D for ‘Inside The Perfect Predator’

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  • © 2010 Mark Payne-Gill
  • © 2010 Mark Payne-Gill
  • © 2010 Mark Payne-Gill

I was introduced to the 3D filming experience while shooting peregrines in 2D for ‘Inside The Perfect Predator’ as part of some tests designed to asses the feasibility of applying 3D cinematography to wildlife productions, highlighting the challenges & problems involved. Now ‘Inside The Perfect Predator is not your typical ‘blue chip wildlife production being very much conceptual in style, filmed under controlled conditions and laden with state of the art special effects. But this did prove an ideal test bed involving various filming situations typically encountered in 2D from long lens, wide angle close ups, highspeed to interior studio & macro.

The principles of filming in 3D seemed at first fairly basic; 2 cameras side by side separated by a distance representative of that between human eyes. Simple! However my first experience in shooting 3D revealed how the many variables involved in creating realistic stereo images for natural history productions makes the process far more challenging. There is much more effort involved in acquiring images we sometimes take for granted in the 2D world.

It became apparent achieving the perfect 3D wildlife film experience requires a much greater understanding between all the disciplines associated with 2D. Indeed I found it was a crucial requirement that the postproduction department, cinematographer, editor, director & producer all collaborate their roles in such a way that there is little margin for errors to creep in. Thus 3D requires very high production values and as such creates a new role to successfully integrate these elements together…that of the stereographer, whose knowledge & experience of the principles of 3D is a crucial part of the team to have on location.

My total experience on this amounted to 5 days plus a few hours tuition prior to shooting, with an introduction to the basic principles of 3D and the camera rig I’d be using. This wasn’t 2 cameras paired side by side, as I naively thought! I was in the deep end and climbed a very steep learning curve on the first day! The camera itself was a mirror rig with a pair of cameras (in this case Sony EX1’s) at 90degrees to each other one horizontal & one vertical both pointing into a single mirror. The advantage this had over a simple parallel camera rig was obvious since being able to adjust the interocular distance between the two cameras is the key to having control over the stereo effect. Instantly the rules & limitations of 3D image acquisition were apparent and my experience with 2D was of little help.

The first scene I filmed involved peregrine chicks being fed by their parent on a set at a falconry centre. With just enough room to squeeze the giant rig into the enclosure the peregrines were in a way the least challenging of the variables we needed to master. Being a basic rig I had to align the cameras by eye using a monitor & flipping back & forth between each cameras image. I also had no means of focus pulling or adjusting exposure for both cameras at the same time while filming. A good depth of field and careful use of shot size allowed for some movement of the subjects without losing focus. I also had to contend with a reversed image, using a monitor as a viewfinder. This made panning extremely counter intuitive, an artifact of the mirror set up! But perhaps the biggest issue was deciding on the distance between the cameras. This mirror rig allowed the camera pair to sit over each other thus allowing for an infinitely variable interocular distance, within a set baseline (unlike a parallel, side by side rig, limited by the width of cameras used) Filming the peregrines with only a few feet focal distance meant we had to shoot with a relatively small interocular distance to achieve an acceptable stereo result. But there seemed to be no fixed rule as to what was the correct interocular distance, apart from if the subject is too close then alignment of the two images doesn’t work. I found the image from one camera had the head of the peregrine halfway out of shot, left of frame where as the other camera image showed the its head nicely in frame just right of centre! In this instance we simply bracketed the baseline for each shot so the correlation between focal and interocular distance could be seen in postproduction. All things one never had to consider in the 2D world!

Framing also needs far more consideration than normally required. Generally we had to leave plenty of room around the subject so nothing clipped the edges of the framing, especially for shots where a peregrine would be flying into the lens and out of the screen, otherwise the wings for example would be cut off as it gets closer to the audience.

An unexpected paradox underlined how differently we have to think for 3D acquisition when setting up a shot to film a simple low wide-angle close up. It has implications for time and cost. Something that might only take a few minutes to set up on a 2D shoot with our trained peregrine but which in 3D required considered planning and two separate shots. The interocular distance needed to be much larger for the sky background than the peregrine in the foreground. Hence the peregrine required a blue screen background, filmed as separate plate to the sky and then combined in postproduction.

The macro shoot involved a different camera rig for peregrine portrait close ups, in a studio environment. We used motorized 3D mirror & parallel rigs supporting two IIS Micro HDTV cameras. The mirror rig placed the two cameras facing each other into prisms that fed the images from a 90 degree angle to the cameras. Here we used very small interocular distances being so close to the subject. The limitations of available equipment became apparent, as the closest macro we could achieve was to barely fill frame with the peregrine’s head. This time I had the luxury of seeing the 3D images live on a large plasma display so the 3D effect could be accurately monitored shot by shot. No guesswork was needed. One of the first rules I learnt was to always visually check the 3D image where possible and never make assumptions, especially if drawing on ones 2D experiences. This is a totally different kind of field craft to what we’re used to!

One of the final set ups involved the peregrine flying into the lens for a dramatic ‘flying out of the screen’ experience. Again, a shot we’re relatively used to filming in 2D and which shouldn’t take too long to set up. However a drawback of the bulky 3D equipment became apparent as the size of the mirror rigs prevented the bird from flying anywhere near the lens, even with a pair of relatively compact Sony HDC X300’s. ‘Good 3D does not come from small cameras’, that’s for sure! At this time there are no off-the-shelve single 3D cameras available so with a shot like this we had to employ a Photron SA2 camera and rely on postproduction to render this into a 3D image.
Fundamental to all the 3D rigs employed was the inability to focus pull both cameras simultaneously, relying on fixed focus distance only. Clearly something which has to be corrected if any serious wildlife filming is to be achieved.

Working closely with an experienced 3D crew including a stereographer for most of this shoot revealed how important all the individual roles in a 3D team are and how closely each member needs to work with one another for the best results. Time is an issue. It may therefore become important for the wildlife cameraman to take on the role of stereographer to speed up the process, being able to make intuitive and on the spot technical decisions where necessary. This process could become easier too, should technology advance enough to allow the production of a single 3D camera unit as opposed to a rig.

Applied to natural history filmmaking 3D creates great possibilities for an immersive experience unlike anything else experienced in 2D. But more planning and time needs to be allowed for acquiring shots. Rig

Author: Mark Payne-Gill