Filming of "Lewis & Clark" in IMAX
Director of Photography, T.C. Christensen interviewed

Left:  DP  T.C. Christensen. Middle: 1st AC  Zep Christensen and right: 2nd AC and writer of article  Kurtis Burr. Picture supplied by T C Christensen

In 1803, the Corps of Discovery was allocated $2,500 and a letter of US credit. Our journey in 2000 cost a bit more. The hard cost involved in shooting IMAX definitely influence all large format DP's. Raw stock averages about $1.15 per foot. Running time for a 1000' roll of film is just under three minutes. The cost of a 35mm print down runs approximately 85 cents per foot. 

The viewer should notice more than a handful of uncommon shots as they watch National Geographic's "Lewis and Clark" IMAX. T.C. spoke about a few of his favorites. During the Corps of Discovery's journey up the Missouri one problem they often encountered was floating logs coming down the river and ramming their boat. These were big trees moving with the speed of the current, sometimes up to 20 mph. "So we decided the most interesting way to shoot this would be to attach the camera to a log. We found a tree floating in the Missouri, the grips attached the camera to it, and my first thought was that I would just watch the shot on video assist. Then it occurred to me that I could ride it. So I climbed up on it, hung off to the side and was able to operate." 

The night before shooting the scene where Lewis slips off a 60 foot cliff above the Missouri, the Director Bruce Neibaur, Producers Lisa Truitt and Jeff Miller along with T.C. got into a discussion on how to make this more of an IMAX event. "We got the idea to try a free fall with the camera representing Lewis' POV. We put the 40mm (very wide) on the camera and Key Grip, Matt Stelling built a go-cart contraption with four rubber wheels, then encased the camera. The go cart would then ride down the angled top section of the cliff while the grips controlled its decent with a rope and pulley system. The camera would descend approximately 60 feet. "At the same time we had the FX guys throwing rocks and dirt down the cliff along side the camera. We did three takes, the best ended up being the first where the camera flipped and rolled over on its back side." Then there was the bear sequence. "In Utah, we have had for many years Bart the Bear, who was probably the most used bear in film and television." He died shortly before preproduction began. Bart's trainer, Doug Seuss is now working a bear named Tank. "Tank is not as big, he is not as well trained, he is not as big a deal to the camera as Bart was. To help this out we came up with the idea of a bear cam. For several shots we took IMAX's Mark II which weighs well over 100 pounds, not the ideal camera for this type of shot." Over 90 % of the film was shot with IMAX's MSM 9801 which weighs just over 60 pounds fully loaded. That camera was not available for the bear sequence. T.C. continued, "The grips built a speed rail support bar to go across the top of this 100 pound camera then two of us, one on either side, would take the Mark II and with a 40mm lens run through brush and alongside the river simulating the bear's POV. I have done this type of shot before and have learned not to shoot it at 24FPS. For me it's a little too bouncy and disorienting. We didn't want to use the 30mm because of the fisheye like quality of that lens. We rolled at 28 FPS and this helped stabilize the camera movement. "There is enough movement so that it has more energy than a Steadicam shot but it is not so erratic that the audience is distracted." Another rig was created by Matt Stelling and Boat Coordinator Larry Matson. The idea was a pontoon mount that would allow the camera to float at water level. "The camera is mounted between pontoons and the lens is only about four inches above the water. I would just swing it around and get a steady moving shot in the water."

A Giraffe crane was used extensively. "It was especially good for this show because it is modular and adaptable. I could ride it by myself and get to a lens height of 24 feet. We had a remote focus system which allowed that configuration to work. If there were two of us on the crane we could go to 16 feet, and with a hothead we could reach 30 feet". There were quite a few shots which necessitated that much reach. T.C.'s preference is however, "If we don't need that much reach, I like to operate through the viewfinder. Then I can look for problems, judge contrast, exposure and focus as well as having a better chance for finding someone's water bottle that may have been left in the shot." 

Asked about choosing film stocks T.C. said, "as a rule, on an IMAX film I need a high speed tungsten and a high speed daylight. You can do anything with them. With the older EXR stocks you could tell a real difference between the low and high speeds, but 5246 and 5279 are so good that you can intermix them and not worry about it. The bulk of the film was shot on 5246, the aerials primarily tended to be 5248. The campfire scenes were 5279 and very often T.C. would push this stock one stop. T.C. rates these stocks 1/3 of a stop under what Kodak rates them, "and then of course there are other considerations such as IMAX's lenses being marked in f-stops as well as the Mark II's smaller shutter angle." These 65mm films from Kodak render these outdoor scenes with breathtaking clarity.

When asked about the films interiors T.C. smiled, "we only got to do one interior location for the whole film; Sacagawea and Charbonneau's quarters at Fort Mandan and the Captain's quarters at the Fort, which was the same set, just redressed. After having done so much daylight exterior, that was fun. 

T.C. has been told by several crew members that this was the most enjoyable film they've ever worked on. "I hope" he said, "that this film will capture the incredible efforts of Lewis and Clark and become a fitting homage to those first Americans who first explored the interior of the continent of North America."

This is T.C. Christensen's 8th large format film. His other's include, Ozarks Legend and Legacy, The Witness, Testaments and Olympic Glory.