From the July/December 1998 issue of the Operating Cameraman

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In the fall of 1994 filmmakers Greg MacGillivray and David Breashears approached IMAX™ corporation with the idea of modifying the IMAX™ Mark II camera for use on Mt. Everest.

MacGillivray knew from experience that the Mark II was a very reliable camera so he wanted to see if lose some weight and be able to function at temperatures as low as minus 40 degrees Fahrenheit.

John Harris, Ken Stone, Stuart Macfarlane and Kevin Kowalchuk of IMAX™ had been working on a lightweight prototype of the Mark II which would bring the camera body weight from 52 pounds to 25 pounds.

MacGillivray Freeman Films and IMAX™ corporation worked together to create the camera that was ultimately used to film on the summit of Mt. Everest at 29,028 feet above see level.

With magazine, film and lens, the original IMAX™ Mark II weighed in at a hefty 75 pounds. The IMAX™ R&D team would take the camera apart, machine or remove parts, re-assemble the camera and weigh it.

The first time they weighed it they thought the scale was wrong--they could not believe that they had actually knocked more than 20 pounds off the camera body.

The main component that reduced the weight was new outside panels which were made of magnesium instead of aluminum. Areas that were not essential to structural integrity were reduced to being paper-thin.

Internally, non-essential components were removed or replaced. Many of the big pieces in the camera such as the motor, circuit boards, digital display and flywheel were replaced with smaller and lighter components.

A major change was omitting the 5-lb flywheel. Previously, it had been used to steady vibrations and to regulate ramp up and deceleration. To compensate for the loss of the flywheel, new electronic circuits were designed.

These were PWM (pulse-width-modulation) circuits where a pulse was introduced to the motor with which, by varying the width of the pulse, the speed of the motor could be varied. This way a certain ramp up speed and deceleration speed could be set without needing the heavy flywheel.

After Shaving pounds off the camera, the design team turned their sights to the many challenges of making it run well in cold weather.

The camera is made up of dissimilar metals such as magnesium, aluminum, stainless steel and steel; all those materials tend to contract at different rates.

Normally if an IMAX™ Mark II camera were frozen to minus 40 degrees Fahrenheit, tolerances within the movement would tighten up enough so that the mechanism would not work.The clearances in areas of the movement that were fairly tight had to be opened up.

For example, the slots that a claw arm had to move within had the tolerances opened up which allowed the mechanism to still function even if it shrank in the severe cold. Every moving part was examined and "opened up" as necessary.

With this re-engineering the camera became quite noisy at room temperature but as the temperature dropped the movement would tighten up and actually become quieter.

Many other small details had to be addressed. A minus 100-degree cold weather lubricant was used on all moving parts. Where possible, plastic bearings that do not require any lubricants were installed.

Rubber belts were replaced with a synthetic rubber that flexed well at lower temperatures, therefore decreasing friction. These friction-reducing measures were employed to make the camera more energy efficient.

Powering the camera was a custom Expedition Battery made by Automated Media Systems. This was a non-rechargeable lithium battery which could run the camera for about 30 rolls of film.

Lithium cells have a chemistry that allows them to give enough output at minus 40 degrees to run a camera.

The expedition batteries were very small and light, weighing only 8 pounds. Silicon jacketed power cables with Teflon coated internal wires were custom built.

Silicon and Teflon remain quite flexible in cold temperatures compared to normal cables which become very stiff. The metal Lemo connectors were jacketed with silicone rubber so hands would not get stuck to them and this also protected the connector from getting ice into it and becoming locked up.

As normal acetate based film stock would get brittle and break easily in low temperatures, it was determined that Kodak Estar based films would be used. The Estar base would not shrink in the cold and was incredibly strong. The film could withstand minus 40-degree temperatures during storage and shooting.

The newly outfitted camera was tested on Mt. Washington, New Hampshire in minus 30-degree temperatures and windy conditions. This was to see if the camera would run at these temperatures and if David Breashears could actually thread the camera with gloves on. The overall performance of the camera was quite good.

After the Mt. Washington tests, extra handles and tie points were put onto the camera body for easier handling.

With all this cold weather testing, it was discovered that some lens modifications were needed because at extreme low temperatures the focus point of the lenses changed. The glass components and internal aluminum parts would shrink so the focal point was different.

In a cold chamber, tests were shot to determine where the actual focal point was at different temperatures. These numbers were scribed onto the lens barrel. The lenses also had to be lubricated with the cold-weather lubricant to prevent locking up at low temperatures.

In 1995, a year before the actual expedition, David Breashears and Kevin Kowalchuk went to Nepal for a 5 week test shoot. The camera ran in conditions as low as minus 40 degrees.

Other testing was done to evaluate shots that would be attempted the following spring high on Mt. Everest. In addition, since this was Breashears' first time shooting IMAX™, he was able to view dailies and get some pointers from MacGillivray, a veteran of the format, before returning in 1996.

In the spring of 1996 Kevin Kowalchuk went to Everest Base Camp and spent a week providing support for the actual summit attempt. Kowalchuk and Brad Ohlund tore the camera apart and checked every small detail.

After making sure it was in good condition and well lubricated, the summit team embarked on their once in a lifetime shoot.

The team never encountered any camera problems and the lightweight Mark II successfully ran 2 rolls of film at the top of the world.

>>Go to part III: The Climb