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James Cameron: Despite Mistakes in Original 'Titanic,' No Changes in 'Titanic 3-D'

James Cameron and Kate Winslet at the "Titanic 3D" premiere in London on March 27, 2012. Jon Furniss/WireImage(LONDON) -- James Cameron, a trailblazing oceanographic explorer, a hugely respected Titanic expert and a perfectionist moviemaker, said that while he discovered a few minor mistakes in his original Titanic, he hasn't changed one frame in his remastered 3-D version.

"There was a moment when I thought fleetingly I could correct the film and actually have it match what Titanic really looked like," Cameron said in an exclusive interview with Nightline. "Another part of my mind said, no, then you're going be a nutter standing on the street corner babbling away."

Movie stars Kate Winslet, Billy Zane and others dazzled on the red carpet in London Tuesday for the world premiere of Titanic 3-D, 15 years after the original film was released. Cameron worked with 300 computer artists, who spent 750,000 man hours giving one of his most iconic films a third dimension. It was a process he called "horrific" and "mind-numbing."

"It has to be done right," he said. "Didn't change a frame. The ship still sinks. Jack still dies."

In the years since the 1997 romantic film became a mega-hit at the box office -- Titanic was the first movie to gross more than $1 billion -- Cameron dipped deeper into his obsession with the "unsinkable ship." The legendary director has dived to the wreck in the North Atlantic 33 times in a submersible vehicle, studying how the real thing compares to his film creation.

"We found places that the set was wrong, little bit, you know, this was wrong, that was wrong," he said. "There was glass missing from a door."

"I thought I'd thought about everything about Titanic," Cameron told Nightline. And then he gathered eight of the world's leading Titanic experts for an upcoming National Geographic documentary called Titanic: The Final Word. The documentary premieres on Sunday, April 8 at 8 p.m. ET on the National Geographic Channel.

Titanic 3-D may almost be historically accurate, but Cameron now knows it is not perfect. For example, he used a little artistic license in the scene where Winslet and DiCaprio are clinging to the ship's railing, way up in the air, as it is being dragged down into icy depths.

"There was actually probably a moment where it was standing quite proud of the water, but it wasn't quite as dramatic and as static as we showed in the film," Cameron said. "It probably wasn't straight up. It was probably at an angle. We realized that it was really just the perspective of some of the eyewitnesses."

He said he hopes Titanic 3-D, which will be out in theaters in April 4, timed to the 100th anniversary of the ship's sinking, will have a powerful impact on the audience.

Cameron nearly missed the Titanic 3-D premiere because, just Monday, he was at the bottom of the Mariana Trench in the Western Pacific, roughly seven miles down in the deepest part of the world's oceans.

Only two other people have ever been down that deep. In 1962, then-Navy Lieutenant Don Walsh and a Swiss co-pilot dove into the trench. More than 50 years later, Cameron made the deep dive alone, down to what he described as a "lunar landscape."

"I've got some good engineers," Cameron said. "If we thought we were going die, diving this sub, we'd be idiots."

Copyright 2012 ABC News Radio

ABC News Radio