As a lead photographer for WireImage, the official photo agency of the Sundance Film Festival, Vespa shoots hundreds of festival actors and filmmakers from a makeshift studio on Park City's Main Street.

"We do portraits of pretty much everybody who attends," said Vespa in an interview this week.

Vespa is a co-founder of WireImage, a digital-photo service that provides images of celebrities, professional athletes and other prominent figures to media outlets worldwide.

Stars now consider Vespa's temporary studio a required stop on their Sundance circuit. The photographer gets anywhere from 5 to 15 minutes for each shoot, which he undertakes without costumes or props.

"My whole shtick is trying to capture people for who they really are," he said. "The challenge is to get people relaxed and comfortable in a short period of time."

Among this week's Sundance attendees, Vespa was especially struck by Diddy's laser focus, William H. Macy's expressive face and Tilda Swinton's brilliant green eyes. But his most memorable shoot may have been of Jack Black and the rest of the "Be Kind Rewind" cast.

"Jack Black was wearing this muscle T-shirt and he kept doing all these muscle-man poses," said Vespa, whose images from Sundance appear in magazines around the world. "He was hilarious."