Sony tells how to make 3-D
Los Angeles— iHollywood Forum, an event partner, hosted a media event entitled “Future of 3-D for film, TV, video, games, mobile, and the Internet” on June 14, 2010.. The second keynote speaker was Buzz Hays, senior vp and GM of the Sony 3-D Technical Center.
To assist filmmakers in creating high-quality 3-D movies, Sony established their 3-D technology center. Here they show people how 3-D works, and help equipment suppliers tell consumers what information they need. The technology for creating 3-D films is available from many vendors, but there still some issues with synchronization between film and digital content creation.
They define high quality 3-D as the illusion of providing the third dimension on the screen. The issues associated with 3-D films are both technical considerations and aesthetic values. 3-D is another tool to support storytelling. It has an immersive effect on viewers, but is not a health issue. The characteristics of parallax and depth help tell the stories, but there are boundaries on the technology.
All of the challenges of digital filming—resolution, misalignment, registration, etc.—are exacerbated in 3-D. For stereo vision, we depend on the spacing of the eyes or inter-ocular distance—about 2 1/2 inches in adults—to provide slightly different views of a scene, which the brain integrates then into a three-dimensional image.
The problem is that stereo cameras cannot match the separation of the eyes. The inter-axial distance in cameras affects the scale of the scene and cannot be changed in postproduction. Convergence, the angle between the camera optical axes, is used to push infinity back. This allows filmmakers to massage the depth in the scene. It is most useful to control this depth effect in postproduction.
Two other physical factors, vertical and scale misalignment, can cause problems for viewers, because these effects do not occur naturally. To address these issues, companies have created camera rigs. For wide shots, cameras can be mounted side-by-side. For other types of shots, the preferred rig uses a beam splitter, because the side-by-side cameras are too far apart. Unfortunately, beam splitters create another problem, a polarization component for the top camera.
For 3-D films, producers must also address the viewers’ physical characteristics. People are not aware they change the angle of motion of their eyes, convergence, and change the point of focus, accommodation. Problems arise when the image on the screen differs from the implied image. These eye focus problems can be addressed by imposing a depth hand off in scene transitions.
Parallax is another depth cue that we take for granted. Positive parallax results when the left side of the image is shifted to the left and the right side of the image is shifted to the right of the object center. Negative parallax reverses these apparent motions. The amount of parallax can be adjusted by changing the inter-axial distance, convergence, or other physical camera attributes. An extreme case results in divergence, where the background pixels go fuzzy, and is impossible fix without some type of conversion.
People use a number of visual cues to indicate depth. In fact, these monocular depth cues have been used in paintings for centuries. These cues include motion parallax, relative parallax, scale, perspective and vanishing point, light and shadow, and textured gradient. Photographers and cinematographers have developed a number of techniques to take advantage of these depth cues. These techniques include selecting of focal points, depth of field, framing, blocking, and camera motion.
Because digital 3-D is fairly new, Sony offers free training and laboratory work for the industry. This training is important because many of the techniques used in traditional filming don’t work in 3-D. They’re presenting programs for cinematographers, film and TV directors, live events proves, game developers, and editors.
