She sees the holes in his shoes, his lucky charms, his lack of sleep and his quieter moments. For 18 months, Callie Shell has enjoyed intimate access to the man who would be the 44th president of the United States of America - and the first black occupant of the White House.

Shell has been there to capture the down moments, the nerves and weariness of Barack Obama on her camera. As the official photographer of the “Change” campaign, she eats, sleeps, travels and lives with her subjects. “I like to be forgotten,” she says. “Then I can document their lives.” But criss-crossing America, Shell has cultivated a unique relationship with Obama. During the New Hampshire primary in January, Obama turned to his wife Michelle on the campaign bus and said: “The reason why Callie and I get along so well is because we’ve both got big ears.”

Michelle turned to Shell and said: “Isn’t it amazing he ever got a wife?” The pair have covered thousands of miles on the road together. “We do get along well,” says Shell. “He’s good-looking and smart.” Watching him working on a speech, his feet up on a table, Shell was amazed to notice that Obama’s shoes had two large holes. “I’m not giving them up,” he said. “I’ve broken them in and they’re not ready to go yet.” Obama is superstitious. She has seen him make speeches with his pockets full of lucky charms. And he keeps routines.

Shell, a 47-year-old from Georgia, was Al Gore’s photographer for eight years when he was Bill Clinton’s vice-president. “Gore didn’t trust me at first — it took him about a year. He was hard, but Obama’s easy.” One of Shell’s favourite pictures on the campaign bus is of Michelle falling asleep on Barack’s shoulder. She also captured the pair standing in a corridor, their heads touching, seizing a rare moment alone.

The first time Shell photographed Obama with his family was in November 2006 before he had decided, officially, to run for the White House. Shell describes the scene: “I’m in his kitchen, he’s helping the girls get ready for school, he’s about to leave for the office and Michelle’s going to leave for the university. And I thought: this is going to change. It’s never going to be the same again. Their life is never going to be the same again.”