People were self-conscious whenever they were photographed. They tended to dress in their finest clothes and have serious expressions in order to convey a sense of their good character, Heiferman says.

"As the 20th century moved on and photography became more widespread, images in advertising, movies and media endorsed different values, a sense of euphoria, and emphasized the need to project a positive personality," he said. "People wanted to be seen as happy and successful in snapshots, not like a stick in the mud."

Stopping to notice the volcano

iReporter Thomas Thomas Jr. definitely conveys a sense of happiness in his online postings. Known among his friends for his handstand pictures around the world, the Staten Island, New York, consultant says he still wants to experience the reality of his trip, which he claims is better than the virtual reality of his postings.

"Traveling with friends tends to make for some lifelong memories but those memories don't need to be posted immediately," wrote Thomas, 37.

"There have definitely been dinners where I've looked around and everyone at the table is doing something on their phones, to which I'd say, 'We're sitting next to a volcano! Update your status later!' You've got to enjoy the moment by actually being in it."

One step removed

Vacationing exclusively through your camera lens can take away from the actual experience of your vacation, says Cantor, the communications professor. Vacations used to be time for families to get away from work and school, spend time together and focus on each other.

"If the parents are constantly answering messages from work and they've got one part of their heads back at the office, that can interfere with their enjoyment of the trip," she said. "If the kids are always texting their friends and are not doing anything with their families, that can interfere with it. If they do it most of the time, they're not really experiencing vacation."

That's not to say that you shouldn't take pictures of your wonderful trip, go back to those pictures and bring back those positive feelings. But if you experience the bulk of your vacation "looking through a lens, you might as well have seen it on TV rather than have been there," Cantor said.

That's why iReporter Jim McClure decided not to rely on his iPhone to document his vacations anymore after testing it as his only camera on a trip to the Canadian Rockies a few years ago.

Dozens of times a day, McClure would shoot images, correct them, upload them to Facebook and Twitter, caption them and respond to previous posts.

"Normally, such behavior would have tempted my wife to push me into a lake, but she was a good sport and put up with my new hobby," he wrote.

Although he enjoyed the response from friends and family as they traveled, "I began to feel like a reporter -- filing stories and images -- as opposed to someone on vacation," he wrote. "This wasn't a bad thing, just different."

He's back to packing his SLR, organizing and editing images after the trip and then sharing them on social media.

Put the camera down

Documentary film maker Brian Palmer, who shoots video, photographs and writes for a living, is sometimes told to put his cameras down.

"I think this drive to collect evidence of one's travel experiences and then to present it as proof to other people for validation is powerful among many of us, pro and non-pro alike," said Palmer, a Brooklyn resident. "The ease of digital capture and transmission via social media may have intensified the tendency, but I'm not sure to what extent. Those who are inclined to live through the lens will, unless stopped.

"I have been able to rein myself in when a travel companion has taken me to task," he said. "I feel things more, and I often see more, paradoxically, because I'm not trying to stuff the world into a 35-millimeter frame."

Has a traveling companion's smart phone ever gotten in the way of a vacation? Has it ever added to your enjoyment of your trip? Please share in the comments below.