Jordan Matter is a one-man flash mob - with a camera.

On a frosty Monday in early December, Matter and two dancers from the Pennsylvania Ballet and one from BalletX are pinballing around downtown, politely commandeering Santa's seat in City Hall's courtyard, an entire block of Addison Street, and a divider in the middle of South Broad Street - during rush hour.

See it. Feel it. Shoot it. That's how Matter works. The eye behind the lens of Dancers Among Us, a 2012 New York Times best seller and an Oprah Magazine best book, says his process "relies on serendipity."

"You have to just be aware and look for things," says Matter, 46, who waited tables and had an acting career before settling on photography. "Once you find it, then that creative energy starts fueling all of us."

Matter's devotion to dancers started five years ago. All the "beautiful" dancer photos he saw were posed in studios, never outdoors in everyday settings - city streets, the beach, the subway.

"I never saw anybody use dancers in context and telling a story," says Matter, who spent much of his childhood in New Hope and Doylestown. "It's ironic because dancers are trained to emote with their bodies."

So began the project that would eventually reward him with museum exhibitions all over the world. With the popularity of the images still growing, Matter has decided to continue photographing dancers "celebrating the joy in everyday" scenes.

He has photographed dancers from major ballet companies across America, but until last spring had not shot dancers from the Pennsylvania Ballet. Not that he didn't want to. Two years ago he saw the company's production of George Balanchine's The Nutcracker and thought it "brilliant." He wrote to the ballet's artistic director but never heard back.

Almost a year later, Elliott Schwartz, owner of the Carol Schwartz Gallery in Chestnut Hill, was in New York at an art show looking for new artists. He wandered into Matter's booth.

"The girl in the booth said, 'Do you sell photographs?' " Schwartz remembers. "I said 'No, but this isn't photography.' "

Schwartz and Matter struck up a friendship that eventually led Matter to spend two days in April photographing Pennsylvania Ballet members in city settings.

"The dancers knew about him from his book," says Schwartz, whose gallery is hosting a show of Matter's work through January. "He had 15 volunteers."

Earlier this month, arriving at 30th Street Station to photograph dancers in holiday scenes, Matter is true to form. "I have no idea what we're going to do," he announces. "I'm hoping for two holiday shots, maybe three."

Elizabeth Mateer, the Sugar Plum Fairy in four shows in this year's Pennsylvania Ballet production of The Nutcracker, just smiles. "He's crazy, but in a good way," says the 24-year-old dancer, who worked with Matter in the spring. "His photos are exciting. He creates cool, interesting work."

And dancers line up to work with him. Matter says it's because he tries to make every shoot an adventure for them.

"I really try to bring joy to every shoot I do," he says.

But working with him is physically demanding. Holding one difficult pose for last spring's shoot left Mateer and the Pennsylvania Ballet's Alexander Peters sore for a week. On this shoot, frostbite is the biggest concern.

"I tend to push dancers to their limit," Matter says. "I do that because I always think it can be better. I think that comes with training as an athlete."

The athlete's mindset is a holdover from his baseball days at the University of Richmond. But it's also why he feels he connects so well with his subjects. Dancers are, after all, elite athletes. A successful double-play pivot isn't as flowing as a grand jeté, but it still demands years of dedication and hard practice to get right.

"Part of my process is physical," he says. "I try my best to demonstrate what I want, not with the grace they have but with whatever is left of my athleticism."

His physicality comes to the fore on Addison Street, where light-wrapped trees turn the block into a fairy-tale forest.

"Oh yeah, there's something here," he says, popping out of the car. "I'm imagining a jump."

In an instant he bounds across the street, knocking on doors to borrow a wreath. He explains his vision to Peters, also a veteran of the spring shoot, saying, "You're young and happy and you can't wait to get this wreath on your door. That's the story."

Peters tries a few warm-up jumps, but they don't align with Matter's vision, so the photographer takes off his coat to demonstrate. Holding the wreath in one hand, he leaps - like a second baseman avoiding a baserunner.

Then he hands the wreath back to Alex and returns to his camera.

"Wow, this is a holiday poster," he says, going from a sitting position to lying flat on his belly.

He snaps frame after frame but it's still not what he wants. So he asks Mateer and the third dancer of the team, BalletX's Richard Villaverde, for some technical advice.

"I have immense respect for the people I'm working with," Matter says later. "When I shot Alex, it was Elizabeth who came up with the pose. The pose I demonstrated is not the pose that he ended up doing." A few shots later Matter crows, "Did I just nail it or did I nail it? OK, do one more."

Later, heading up Broad Street toward City Hall as the blue drains from the afternoon sky, Matter yells for the car to pull over.

"I like the sky behind City Hall and the purple lights and the yellow clock. We have got to get this shot before it goes black," he says, asking Mateer to slip into a sleeveless, sheer-as-tissue-paper cocktail dress. On the traffic island surrounded by cars and almost directly across from the Academy of Music, Villaverde lifts Mateer high overhead.

"Beautiful, guys, amazing," Matter says, sitting on the ground 15 yards away. "Oh my God, this is going to be so beautiful."