American Cinematographer - April 2008 - (Page 53)

would apply to an object that appears to be behind the screen. Proscenium Arch: For our purposes, this refers to the edge of the screen when an object becomes occluded. Interocular (also called Interaxial): The distance between your eyes. In 3-D, this term more commonly refers to the distance between the left-eye and right-eye taking lenses. In proper 3-D cinematography, the interocular distance between the taking lenses needs to be calculated on a shot-by-shot basis, and it must take into account an average of the viewing conditions in which the motion picture will be screened. For large-screen presentations, the distance is often much less than the distance between an average pair of human eyes. Within reason, the interocular can be altered to exaggerate or minimize the 3-D effect (Fig. 3). The 3-D cinematographer must weigh several factors when determining the appropriate interocular for a shot: the focal length of the taking lenses, the average size of the screen on which the film will be projected, continuity with the next shot in the final edit, and whether it’s necessary to have a dynamic interocular that will change during the shot. Because the interocular distances are crafted for a specific theatrical presentation, a 3-D motion picture doesn’t easily drop into a smaller home-viewing environment. The movie usually will require adaptation and modification of the interocular distances in order to work effectively in such an environment. The facts presented in this article are indisputable, but once you become enmeshed in the world of 3-D, you will encounter many differing opinions on the appropriate ways to photograph and project a 3-D image. For example, when you’re originating images for largeformat 3-D presentations (Imax, Iwerks, etc.), some people will direct you to photograph images in ways that differ from the methods used for 1.85:1 or 2.40:1 presentations. Part of this is due to the requirements for creating stereoscopic illusions in a large-screen (rather than small-screen) environment, but approaches also derive from personal preferences. Many think stereoscopic cinematography involves merely adding an additional camera to mimic the left-eye/right-eye way we see the world, and everything else about the image-making process remains the same. If that were the case, this article wouldn’t be necessary. First off, “3-D” movies are not actually three-dimensional. 3-D movies hinge on visual cues to your brain that trigger depth stimuli, which in turn create an illusion resembling our 3-D depth perception. In a theatrical environment, American Cinematographer 53

Table of Contents Feed for the Digital Edition of American Cinematographer - April 2008

American Cinematographer - April 2008 Contents Editor's Note Global Village: The Counterfeiters Short Takes: Milia Production Slate: Paranoid Park Production Slate: All the Boys Love Mandy Lane Card Sharks Temple of Doom 3-D Cinematography Sundance 2008: Mining for Movies Post Focus: Digital Film Tree Gets into Peyote Post Focus: FotoKem’s 3-D Workflow Post Focus: Technicolor Digs in at Pinewood Filmmakers’ Forum: Steven Fierberg, ASC on Searchers 2.0 New Products & Services International Marketplace Classified Ads Ad Index Clubhouse News ASC Close-Up: Rodney Taylor

American Cinematographer - April 2008

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