The Stereoscopic 3D Experience
Stereographic graphic services for TOXIN 3D were provided by Vancouver's Aexcea Inc.
To answer the production call of the independent feature film TOXIN 3D, shot locally in Vancouver, Aexcea Inc. developed its own S3D (stereoscopic) beam-splitter camera rig and 3D stereoscopic editorial system. The choice was made to utilize 2 cameras in combination with select 2D to 3D conversion rather than a prism based system in order to maintain the full cinematic scope of the production with no loss due to frame width compression.
While such systems have existed for a long time, this process was experimental, representing the first time a production of this scope and scale has ever been filmed in this manner, and made use of "off the shelf" camera equipment such as the Canon 5D MKII to match the target budget of the production. The innovative use of dual Canon 5D MK II cameras presents a number of interesting challenges including shutter synchronization, focus and the focal length of the lens.
Frame synchronization was achieved using a hardware camera control device invented in Estonia. This device, the CAMRemote allows the synchronization of multiple cameras to a single shutter trigger event. It's a concept similar to that used for the "Bullet Time" effect made popular in the feature film "The Matrix."
Okay...but how does it work? It's really quite simple. Hold your index finger up and out in front of you. Now close your left eye and look at your finger...in particular what's behind your finger. Now open your left eye and close your right eye and look at what's behind your finger. It's almost as the whole world has moved a bit. What you're seeing is the difference between the two lines of sight from the left to the right eye. The distance between the centers of your eyes is referred to as Interoctal distance and averages about 2.5 inches (depending on how big your head is!). 3D cinema works in a similar way. We shoot with 2 cameras...one representing the left eye, one the right. We position the cameras apart from each other (referred to as Interaxial distance) and best try to replicate what the human eye would see. The two differing lines of sight provide us with a sense of depth.
Because the Canon 5D MKII cameras are of a specific physical size that cannot be changed, the interaxial distance between two Canon's placed side by side is about 5.5 inches. Much to wide for an enjoyable 3D experience. To compensate for this, we placed one camera overtop of the other at a 90 degree angle. We used a special piece of glass between the two cameras positioned at a 45 degree angle. This rig is referred to as a "beam splitter" rig and allowed us to adjust the interaxial distance ranging from zero centimeters to as much as 10 centimeters.