It was the beginning of what would be a long day for the then-future president of the United States, Barack Obama. He’d finished up on the campaign trail about 1 a.m., then returned to his hotel to steal a few hours of sleep with Michelle, who had been busy campaigning separately from her husband. Now the two were gearing up for that day’s primary in New Hampshire. Their paths would diverge again that morning, but first there was a 20-minute bus ride, their only chance for some quiet time alone together. When they would have that chance again was anybody’s guess.

As usual, alone was a relative term. Campaigning, they were always surrounded by staffers, supporters, and of course, photographers. On that morning, as Mr. Obama skimmed through the newspaper, his wife nestled her head into his shoulder and rested her eyes.

Carefully, considerately, Time photographer Callie Shell snapped a photo of the quiet couple. It was a private, intimate moment between husband and wife, one that might have been exploited by another photojournalist. But as a White House photographer, and then as a Time photographer for the Obama presidential campaign, Ms. Shell had learned the value of keeping a respectful distance. In return, she was granted exclusive access to these private moments.

“I don’t think I would have had the trust, if I’d just started, the first time they’d ever met me,” she said in an interview this week. “But I think because I’d been covering him for a while, I just don’t think she cared.”

The photograph is part of a collection from the Obama campaign trail that will be on display at the Simon Gallery, beginning Sunday, August 22. Of the vast collection of photos Ms. Shell shot in the course of the campaign, it is the one of which she is most proud. “I wanted something that showed their relationship, and their friendship,” she said. “Not only are they husband and wife but they’re best friends.”

Most people expect her to have forged a fast friendship with Mr. Obama, Ms. Shell said. They expect stories exposing details of his real persona, a glimpse into the mind’s eye of the U.S. President. She hates to disappoint, especially because her experiences with Mr. Obama have been so kind and gracious in the years since he first caught her eye, as a candidate for U.S. Senate in 2004.

But the reality is somewhat different. “I photograph this man. I’m not best friends with him, and most people want you to be,” she said.

As an observer over the past six years, she can tell you that the President is patient, funny and incredibly hard-working. She relates to him much more than her previous subjects, such as Al Gore, whom she photographed as a White House photographer during President Clinton’s tenure in office.

“We’re both tall, with the big ears,” she joked. But it goes a little deeper than that. They are both parents, for instance, and have a child of the same age. And the demands of their jobs take them away from their children more than they’d like to be.

Their marriages, too, share similar traits. “We both feel like we married up in life, and the best part of each of us is the person we married,” she said.

Ms. Shell is married to a National Geographic photographer, whose job, she said, was considered infinitely cooler than hers by their almost-nine-year-old son, Hunter. At least before the Obamas came into the picture.

“When people would ask my son, what do your parents do, he would always go, oh my dad works for this cool yellow magazine called National Geographic, and he photographs animals and goes all over the world,” she said. And what about mom? “Oh, my mom just works for this boring red magazine,” mimicked Ms. Shell, laughing. But she finally got some validation once she started shooting Mr. Obama. “He did think Obama was cool,” she said. “And when he met the president, he was so nice to my son.”

Their professional relationship began while Ms. Shell was following Sen. John Kerry on his own presidential campaign trail in 2004. At an event in Chicago, the then largely unknown Barack Obama introduced Mr. Kerry, and Ms. Shell was a bit taken with the senatorial candidate. “When I met him in Chicago, he was really personable, and he said hello to everyone, and was engaging,” she said. “So from a photographer’s standpoint, it’s always good to find someone who actually likes to be around people and talk to people.”

While most people at the event were looking to Senator Kerry as presidential material, Ms. Shell saw the real potential in Mr. Obama. “I took all these photographs of him at the Kerry event. My editor was like, ‘I guess you really like this guy.’ I said, ‘I think he’s great, I think he’s going to run for president some day,’” she recalled. At the time, she said she remembers thinking that there would be a need for a man like Mr. Obama in the presidency, and soon. “I thought he would [win] in the next election. I think when I first said that to Time, they thought I was crazy,” she said.

But her instinct led her to the job on Mr. Obama’s campaign trail, where she found one of his best traits as a politician was his willingness to address adversity from the American public. “A lot of politicians shy away from protestors,” she said. “He would walk right up to them and talk to them.” He was also an excellent listener, and genuinely concerned about the troubles of others. “He always was interested in what everyone had to say. You would see white, black, male, female, old and young really react to him and become engaged . . . He really listens when somebody talks to him. He’s interested. And people can see through the ones who aren’t,” she said.

Ms. Shell said she hasn’t seen much of a change in the president since he took office. Though she turned down an invitation to be the Obamas’ official White House photographer, she’s returned for smaller projects since he took office, and recognizes the same gracious, funny guy he always was. Of course the hours have changed. And so has the privacy. “It’s the loneliest job in the world, I think, where you’re never alone. There are always people around you,” she said of the presidency. But she still thinks he was a good fit for the job.

Ms. Shell will not be traveling to the Island to capture the President’s family vacation, nor will she be able to attend the Simon Gallery show. Instead, she’s busy at home in South Carolina, preparing her son for his first day back to school. And despite the excitement of life on the road with a would-be president, or long hours on assignment covering stately events in the capital, she’s happy she got the summer at home. “During the nine years that he’s been alive, it’s my first summer off, and not shooting or working,” she said.

The Callie Shell photography exhibit opens Sunday at the Simon Gallery on Main street, Vineyard Haven. A reception begins at 5 p.m. All are welcome.