Common sense might dictate that when a volcano starts erupting, the best thing to do is run away. But for a small and somewhat obsessed band of photographers, news of a new lava-spewing giant somewhere in the world means one thing: It's time to book a flight.

In early April, Martin Rietze spent three sleepless nights huddled next to a large boulder about 1,600 feet from the mouth of Iceland's recently reawakened Eyjafjallajokull volcano, having the time of his life.

Sleepless because when a volcano is throwing car-sized pieces of rock into the air, you can't close your eyes for a second. "It's too dangerous to sleep, so you have to stay up," he said from his home in Eichenau, Germany.

Rietze, an engineer who builds delicate electronics for planetariums, is part of a very small group of mostly men worldwide who spend vacations racing to be as near as possible to molten magma, choking ash clouds and poisonous gases, not to mention a rain of smoking-hot boulders.

Volcanophiles exist all over the world, though there are at best only a couple hundred of them, they estimate. There are groups and individuals in Germany, the Netherlands, Belgium, Switzerland, France, the U.S. and Japan.

They seem to include a high percentage of engineers, computer, electrical, chemical and mechanical. Though it once was a solitary pursuit, the Internet has allowed them to share their work — and tips.

It's a labor of love, because they all know they can't make a living at it, said Richard Roscoe, an Englishman who works as a patent examiner in the European Patent Office. He's spending this week in Vanuatu to shoot the Yasur volcano.

"One always hopes that one will get the really big shot and get that contract with National Geographic, but the likelihood is very minimal," he said.

But professionals urge a large dose of caution. Volcanoes are astoundingly alluring; far too many people take far too many chances around them, said Donna and Steve O'Meara, a husband-and-wife team who shoot for National Geographic. "They put fire in people's eyes and their brain is left behind," Donna said.

Even the most experienced can lose their lives. Volcanologists Katia and Maurice Krafft from France and Harry Glicken from the U.S. died in an eruption on Mount Unzen in Japan on June 3, 1991, along with 41 journalists.

Seeing an eruption in progress is "very humbling to experience, frightening and awe-inspiring," said Jim Stimac. A geothermal engineer, he lives in Jakarta, Indonesia, and belongs to Java Lava, a local group that hikes to volcanoes. But he said they strive to be as cautious as possible.

Professional geologists and volcanologists "think we're mad, basically," Roscoe said.

Though not all in the academic community disdain them. Richard Wunderman, who edits the Bulletin of the Global Volcanism Network for the Smithsonian Institution in Washington, D.C., said he often relies on amateurs for reports and photos of eruptions that would otherwise go unrecorded. "They're an amazing resource," he said.

The hardest part about capturing the raw power of a volcano in a photo isn't getting close enough, but getting a clear view, said Arnold Binas, a computer scientist in Sydney. Clouds, fog and steam often block the view, he says. "Patience is the key."

Safety gear is also critical, said Patrick Koster, 41, of Spijkenisse in the Netherlands. A chemical engineer, he wears a climbing helmet, goggles, a gas mask to filter ash and neutralize chemicals in the gases emitted by the volcanoes and gloves. They're "very important because fresh lava can be razor-sharp, so if you put your hand down, you can get cut badly," he said.

Most volcanoes erupt in distant, difficult-to-access places.

Eyjafjallajokull was "awesome" because it was accessible without being overrun with tourists, said Sean Stiegemeier, 26, a Los Angeles cinematographer.

"The one good day of weather we were there, there were probably 10 cars out next to the volcano, most of them photographers with gigantic lenses," he said. "It was so loud, every now and again it felt like it was rumbling its stomach at us and then it would spit out lava."