People walk past a huge "Avatar" amp suit at the Mattel booth at Comic-Con International 2009 Convention held in San Diego .

Cameron said he wanted to have the film-making techniques fade into the background as the story took over.

"The ideal movie technology is so advanced that it waves a magic wand and makes itself disappear," he said.

Cameron himself was behind the lens in many scenes that were framed using a "virtual camera" - a handheld monitor that lets the director walk through the computer-enhanced 3D scene and record it as if he were the cameraman.

The effect on screen is a "shaky cam" effect that makes action sequences seem up close and sometimes focuses the audience's gaze at something in particular.

"It allows Jim to approach this process with the same sensibilities that he would have approached live-action filming," said producer Jon Landau.

The ability to capture human emotions in computerized 3D has also advanced.

Unlike past methods that captured dots placed on human faces to trace movements that are reconstructed digitally, now each frame is analyzed for facial details such as pores and wrinkles that help recreate a moving computerized image.

"It's all going to advance the whole concept of 3D one leap higher," said Marty Shindler, a film-making consultant with The Shindler Perspective Inc.

Yet even with four years of preparation and the attention surrounding "Avatar," there will not be enough screens adapted to the technology for a full wide release only in 3D across the United States.

Of the 38,800 movie screens in the US, about 2,500 are capable of showing digital 3D movies. Theater chains have been adding about 90 to 100 per month this year, but they're still short of the 4,000-plus screens that have been used for major event movies.

With the conversion costing US$100,000 a pop, theater owners are wary of moving too quickly, said Patrick Corcoran, director of media and research for the National Association of Theater Owners.

"The successes of 'Monsters vs Aliens' and 'Ice Age 3: Dawn of the Dinosaurs' aside, this is still really early days for this format," he said.

Convert

Studios are pushing theater owners to convert more screens, partly because people pay about US$2 more per ticket and cram theaters for 3D releases. Revenue per screen is up to three times higher than for the same movie's 2D version.

Walt Disney Co's chief executive, Bob Iger, said last week that his studio has 17 3D films in development, including "A Christmas Carol." That movie, directed by Robert Zemeckis, adopted many of the same performance-capture techniques used in "Avatar" but comes out a month earlier, in November.

Jovan Cohn, a 43-year-old systems engineer from Newport Beach, California, watched the "Avatar" preview at Comic-Con and expects to line up with his son for another free look on August 21, when some IMAX theaters will show 15 minutes of the film. Cohn also plans to catch the full movie's release on December 18.

"It takes you into a new world of moviegoing and we really think that it's going to be a hit," he said. "No question on that. James Cameron just hit another home run."

(Shanghai Daily July 30, 2009)