American Cinematographer - April 2011 - 53

eyes are aligned in parallel; when something is close enough, we can go practically cross-eyed. Our brain has the ability to sense that an object viewed at a certain convergence angle is a certain distance away. 3-D is about creating this “illusion” of depth in ways that add enjoyment to the motion-imaging experience. With 2-D images, like paintings, we discern what would be the relative depths of objects in them if they existed in the real world. Visual cues such as one object blocking portions of another, and one object appearing larger than another of similar design, suggest that the larger, unobstructed object is nearer. We use these and other cues regularly in photos and movies, satisfying ourselves that what we see in 2-D can adequately represent the scene in the real world, but minus the third dimension. Anyone who has donned paperframed 3-D glasses is familiar with the basic concept behind how filters separate left-eye and right-eye views. The “anaglyph” process typically uses complementary color filter pairs, meaning colors on opposite sides of the traditional color wheel — for example, red and cyan, which form gray or black when combined. Light transmitted through one filter won’t pass through the other. The darker the result, the less cross-talk there will be. Called “ghosting,” this is when one eye sees a vestige of what the other eye sees, diminishing some of the illusion of depth. The lefteye view is presented through one such filter; the right-eye through its complement. Superimposing each view over the other without the aid of eyeglasses, the image looks fuzzy, with color fringing. Seen through glasses, each eye sees only what it should; the image clarifies, taking on the illusion of depth. The color pairs mentioned above work best for black-and-white imaging, where there is no concern for subtleties of color in the combined image. With some tweaking, they also find use in full-color imaging. Gene Dolgoff, CEO of 3-D Vision in Westbury, N.Y., and an inven-

Opposite: An Element Technica Quasar rig with side-by-side cameras is used to shoot the World Cup. This page, top: Red One cameras mounted on a 21st Century 3D BX-3 beamsplitter rig. Below: This diagram of a beamsplitter rig reveals the paths of direct and reflected image-forming light and the key areas of difficulty in matching both eye views.

Images courtesy of 21st Century 3D, Element Technica, Screen Plane and the author.

tor with a long history of pioneering work in 3-D techniques (including holography), uses what he calls the “FullColor 3-D” color pair of green and purple. His view is that these colors have a more even balance of light transmission, producing brighter, more vivid color than red/cyan. He maintains that they also reduce ghosting from the
www.theasc.com

red/green/blue primary colors of television. Liquid-crystal-display shutter glasses are able to alternately transmit and then block vision through the two eyeglass lenses, in electronic synchronization with the appropriate displayed view for each eye. Because the sync must be actively maintained between the
April 2011 53

http://www.theasc.com

American Cinematographer - April 2011

Table of Contents for the Digital Edition of American Cinematographer - April 2011