Feature: Sanctum

By Rodney Appleyard

Wetset Solutions’ Simon Christidis knows about danger.

He is one of the few divers in the world to swim through The Room of Tears in Mexico, spending an hour and a half some two kilometres below the surface to traverse the dangerous underwater cave.

Now, the cameraman will use his years of underwater filming experience to take specially designed 3D cameras through their paces on new Australian feature film Sanctum.

Renowned filmmaker James Cameron is executive producing the film, which will be partly filmed inside Warner Brothers’ giant Gold Coast-based water tank. Jules O’Loughlin is the cinematographer.

The $30 million Sanctum tells the true story of a group of adrenaline junkie divers who risk their lives during an expedition to the unexplored and least accessible cave system in the world – the Nullarbor caves. 

Australian writer Andrew White penned the script while Alister Grierson has been enlisted to direct.

Cameron and his cinematographer on 3D odyssey Avatar, Vince Pace, developed a new camera system for that film, which allows viewers to experience 3D as if they are looking through a window frame.

“Other kinds of 3D annoy people because you usually get so many flying limbs in front of your face, which are usually out of focus,” Christidis says.

“But this “window frame” technique means that everything you see is like looking through a window. Although everything beyond the window has a 3D depth to it, nothing in front of the window frame is in 3D, so everything is always in focus.”

Christidis was chosen to film the underwater action due to his years of expertise with underwater camera systems, which includes work on Flipper, Nim’s Island and H20.

He has also developed special camera housing that allows him to deal with difficult underwater scenarios. For instance, he has invented a web port system that absorbs water when filming on the surface of the sea so the lens never records splashes that can compromise the image.

“There is a real art involved with filming underwater,” Christidis says.

“You need to be able to hold the camera steady, especially when you are floating over a reef, or have surf crashing down around you. You also need to be able to pull out the focus at the right speed, which involves careful buoyancy. On top of that, you have to be aware of what the actors are doing around you underwater. It’s a very specialised skill.”

Christidis says that the production was attracted to Queensland because the tank provides the best opportunity in the world for underwater filming.

“Nobody else has a tank that is so versatile as this 25 metre by 50 metre tank. It can clean out all of the dirty water and have it filled up with fresh water in just an hour and a half, leaving you with incredibly clear water.

“This is down to its huge filtration system. It’s important because if you have pollution like paint in the water, you need to flush it out as quickly as possible.

“It can also be heated to phenomenal temperatures. On top of that, in places it’s 10 metres deep, which allows you to film action that looks about 100 metres deep.”

A replica version of the Nullarbor cave system has been created in the tanks.

“The idea behind using the 3D cameras is to make the viewer feel like they are actually swim around these caves too."