Monday, March 26, 2007

IMAX Sound Systems

IMAX sound has always been generations ahead of nominal theater systems. Early systems used a 6 track plus sub-bass audio tape system synced to the film.

Over time this was replaced with a CD based system. The IMAX sound systems (by Sonics which IMAX purchased long ago) feature a full 10 octave dynamic range while even modern conventional systems are limited to 6 octaves.

A classic IMAX theater uses 44 speakers and up to 36,000 watts to power the speakers. MPX theaters may be anywhere from minimally better than other theaters to a full blown IMAX system depending on the contracts and costs.

IMAX Projectors

The original IMAX projector was massive. It was also capable of both 24 and 48 fps projection. This is the first permanent IMAX installed.

IMAX created GT (Grand Theater) and SR (cost reduced) products still targetted mostly to museums.

The MPX product is very different and sized to fit in multiplex theaters. 3D capability is pre-built into a single relatively compact projector.

IMAX was an early participant in Digital Projection although originally targetted as a business expansion rather than a replacement or competition for the mainline IMAX product. DPI was bought and then sold in 1999-2001 but did create and release a "DigIMAX" projector line.

The most recent plans as of early 2007 are to use 2 Sony SXRD 4K projectors with some IMAX customizations. This would not provide "IMAX" level 15/70 picture quality but should be far better than other Digital alternatives and if successful could lead to true IMAX level digital projection.

IMAX 3D Glasses

IMAX pioneered much of modern 3D systems.

Best by far were the LCD shutter glasses some with an integral 2 channel personal stereo system which enhanced the 6 channel uncompressed digital theater sound system which IMAX uses.

With E3D LCD glasses one eye is blanked out while the other eye is transparent (or really partially transparent) as the right and left eye images alternate on the screen.

Headset costs and the requirements for cleaning, collection, maintainance and labour has limited the electronic E3D headset use. Next best is the P3D polarized glasses and IMAX has used re-usable large plastic polarized glasses which are far better than low-grade paper glasses. Both left and right eye image are projected simultaneously on the screen through polarizing filters which complement the polarized filters in the glasses. These glasses still require collection and cleaning. DMR/MPX theaters will likely go to the even lower cost disposable glasses similar to those used by competing lowend 3D systems.

Sunday, March 25, 2007

IMAX Cameras

The size of film stock means IMAX cameras will always be large, or have a very limited cartridge size and duration of a single shot.

Deep Sea used a full sized IMAX 3D Solido camera in a custom housing.

Cameras used for IMAX productions have ranged from very large to very compact.

The camera used for Everest was small, light, and weatherproof but could only shoot just over a minute of film at a time.

An IMAX collection

I have always loved IMAX. Here is a collection of various IMAX images from technology to theaters to films. Where the images indicate a copyright I have provided a link to the site where you can view and explore.

If an image is not viewable, try clicking on it. If you have a viewer available it will provide the ability to see a larger image.