The biggest critics of James Cameron's Sanctum were those who claimed that the filmmakers didn't know how to shoot 3D, director Alister Grierson told a SMPTE session this morning.
"You just scratch your head and say 'the biggest practitioner of 3D in the world oversaw the creatives of this picture, and you're telling him that he doesn't know how to do 3D,'" Grierson said.
"We had no pretensions to say it was a great work of art, that was never our intention. But as an experience – we did a really great job."
The director signed on to make the claustrophobic cave thriller before the release of Cameron's Avatar sparked a worldwide 3D craze.
"The film would never have existed if the decision hadn't been made to make it in 3D," said Grierson, adding that Cameron wanted to show it was conceivable to make a modestly-budgeted 3D film.
Sanctum was shot with two types of 3D camera – both of which had been used to shoot Avatar. Above water sequences were shot with Sony F950s on beam splitter rigs, while underwater shoots were completed with side-by-side F950 rigs.
"It's almost a ten year old technology, the F900s, which means it probably wasn't the most appropriate tool to shoot in caves," said the film's DoP, Jules O'Loughlin ACS.
"It was a tough film to shoot regardless of whether it was in 3D," said Grierson. "There was so much water on set – as you can imagine, as soon as there's water on set, it just slows down."
The large crew and the issue of lighting a cavern were also contributing difficulties, but O'Loughlin revealed that it was 3D technical issues that had a signifcant impact on day-to-day shooting.
"At the beginning of the shoot, we were losing about an hour and a half," he said. "Towards the end, we had that down to about 20 minutes."
While the enthusiasm for 3D in English-speaking territories has waned, Sanctum grossed $85 million in non-English-speaking countries.
"They're still mad for 3D as a concept," said Grierson.
When asked whether he would shoot Sanctum in 3D again, O'Loughlin said he would, but only under certain circumstances.
"The director, the stereographer and the cinematographer would have complete control over the 3D," he said. "And I would be very much pushing to rid the word 'subtle' from our vernacular and really push the 3D."