Based on the size and scope of Imax films, it would be natural to assume that the corresponding film equipment must be the ultimate in high-tech, cutting-edge technology, light years ahead of the 35mm camera realm. Not so, says Chris Blum, camera department manager of California-based MacGillivray Freeman Films (Everest). ‘With large-format filmmaking, the technology for most of the cameras and camera equipment is nowhere near what it is with 35mm equipment. It’s a lot less advanced. The 35mm world is a good 20 years ahead.’
The most significant difference between large-format and 35mm camera equipment is size and bulk. When preparing to film Everest, Greg MacGillivray approached IMAX and asked them to come up with a lightweight version of their 88-pound Mark II camera. According to info from IMAX, staffers replaced motors and electronics with lighter materials, eliminated the flywheel and substituted magnesium body panels for aluminum. The resulting Lightweight MkII was a trim 38 pounds.
By comparison, the operating weight of a 35mm camera (like the Arriflex 535B) averages about 30lbs, an HDcam (like the Sony HDW790WS) weighs around 16lbs, and a digiBeta (like the Sony DVW700A) is about15lbs.
Large-format filmmakers also have a more limited selection. ‘At this point in time, there are only three or four different camera to choose from,’ Blum says. ‘One of those cameras, although it is the most reliable of them all, was designed 20 years ago.’ (Blum is referring to the regular MkII, which IMAX describes as `rugged and reliable, if heavy.’) ‘The most advanced [large-format] camera available right now is still ten years old. And it’s the closest thing there is to some of the features you can get in a 35mm camera.’
If the sky was the limit, Blum knows exactly what he’d ask for. ‘The ultimate Imax system would be a hand-held, 35-pound camera, with fast lenses, autofocus and digital [capacity], so you’re not carrying around hundreds of rolls of film.’ Blum explains that 1,000 feet of film is only three minutes, and one roll of film weighs ten pounds. ‘The ultimate would be a big video camera, but that gives you the high resolution for Imax that you’d expect.’
Looking beyond cameras, Blum dreams of fast, sharp lenses. ‘For most of the large-format work we do we use Hasselblad lenses from still cameras, which are not very fast in terms of their aperture openings, and when you do use them at their fastest aperture, they’re not very sharp,’ he says. ‘That would be essentially a 40mm F1.0 lens, if you want to put it into one term – the people at IMAX will probably just crack up when they read that.’
Evolution of a medium
by Peter Vamos – Playback
* The camera: Commissioned by IMAX in 1968, Norwegian inventor Jan Jacobson built the prototype Imax movie camera in two-and-a-half months. The camera uses the world’s largest film stock – a 15-perforation, 70mm frame, which is ten times the size of a conventional 35mm frame.
* The projector: Imax projectors use a ‘rolling loop’ system, invented by Australian Ronald Jones, that horizontally advances the film in a wave-like motion. The film runs through at 24 frames per second. The projection lamp is 15,000 watts, bright enough to be seen from outer space.
* The screen: The giant screen, which reaches up to eight stories high, is perforated with thousands of tiny holes to allow sound to flow through unimpeded.
* The sound: Imax uses a six-channel, multi-way digital sound system, manufactured by Sonics Associates, with strategically placed speakers behind the screen – above, below, right, left, plus a sub-bass. Another two speakers reside outside the screen to surround the viewer with sound.
* The 3D camera: Two lenses are precisely spaced to match the distance between human eyes. This interocular distance allows each lens to capture a left- and right-eye view of an object. The images register onto two separate rolls of film, which run simultaneously through the camera.
* The 3D GT Projector: To enable 3D, twin lenses alternately project left- and right-eye images that run on a dual strip of film. The strips run through at 24 fps, while the shutter alternates between left- and right-eye images 96 times per second. The GT is water-cooled and weighs 2,000 pounds.