There is one thing that photographers almost universally need to make photographs: light.  But for National Geographic magazine staff photographer Mark Theissen, is drawn not just to light, but to fire.

“As a photographer you are drawn to light and I like photographs that have a light source within them.” Mark explains.

In the October issue of National Geographic, for a story marking 50 years of space exploration, Mark made a frame of spacecraft reentry tiles being tested using concentrated solar rays. Mark was permitted to get close to where the focused beams hit the tiles simulating the intense heat encountered when braking through the Earth’s atmosphere.

To get the shot he wanted he had to mount his camera with a 16mm lens on a mono-pole rigged with a remote trigger. The solar beams were so bright that the exposure was darker than would be used for even bright sunlight: f16 at 1/2000th of a second. That is why the background, which was in full sun, actually appears as if at night in the published frame.

Was the situation very hot? Actually the beam is so concentrated that there was ice on the flooring where Mark was standing. “I had to wear special dark glasses, but the temperature was quite comfortable.” But Mark also noted that occasional small puffs of smoke confirmed the intense heat, as unwitting insects wandered into the path of the rays and instantly vaporized.

But that’s not the end of the story. Mark has also been working on a personal project on wildland firefighters for the last ten years.

To do this Mark has attended fire fighting school so that he could obtain the accreditation to shoot near fires, but to also become more proficient at fire safety.

Once while shooting in Idaho, Mark was cut off by a rapidly advancing fire and had to make a long dash to get out ahead of it. Later he realized that he had been working in an area of overgrown brush which “was like standing in unlit gasoline,” Mark explained. “I've since learned the counter-intuitive sounding advice of ‘one foot in the black, and you will come back’. You will be safe if you get to where there is no fuel, such as an area that has already burned through.”

That is advice I am happy that Mark is taking to heart, since he is currently working on a story for the magazine on firefighters to run next summer.

Check out more of Mark’s photographs from the Space at Fifty story.

— David Griffin, Director of Photography

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