Chris Lem has been a fan of Supergirl — Superman’s younger, female counterpart — for about 30 years, so it was a pretty cool moment when he got to chat with Laura Vandervoort, the Canadian actress who played the character in the old “Smallville” series on The CW network.

“You’re actually the reason I drove up here,” said Lem, a 46-year-old English teacher from Gainesville, Virginia, and one of hundreds of attendees at the Shore Leave 41 science fiction convention at the Delta Hotels Marriott in Hunt Valley on Saturday.

Vandervoort, a little under the weather and sipping a coffee, shot back a convincing, made-for-TV grin. “Aw, stop it!” she said. “Thank you!”

A moment later, Lem had dropped $40 on an autographed picture and said he planned to return to Vandervoort’s table a little later — maybe to drop more cash. “She said come back later for a selfie, so I’m coming back,” he said.

Such interactions are set to occur all weekend — through Sunday — as the fan-run convention celebrates its 41st year of fun. It’s all a little nerdy, but unapologetically so, which makes it kind of cool, attendees said.

Shore Leave is still largely steeped in the sci-fi world of “Star Trek” and “Star Wars,” which have been crowded out at other conventions by anime and the massively popular Marvel Universe, some attendees said.

It’s also smaller and more intimate, which increases the likelihood of making friends you’ll keep for years and meeting your heroes up close and personal, rather than catching a glimpse of them on a stage from the back of a hotel ballroom, they said.

A big draw Saturday was Nichelle Nichols, who played Lt. Uhura in the first “Star Trek” television series that aired from 1966 to 1969. There was also a large contingent of actors from “Smallville,” which ran from 2001 to 2011, several of whom have gone on to play additional sci-fi characters.

“The reason that we continue to work is because fans like this love the genre and like to see you cast in different roles in the genre,” said Vandervoort, who’s been on the convention circuit for 15 years. “Meeting the fans and hearing their passion for the projects that we work on and hearing their stories about how the shows helped them is why we come.”

Aaron Ashmore, who played the character Jimmy Olsen on “Smallville,” agreed.

“It’s fun for us as well. We get to come here and talk to people who enjoy the work that we do, and promote the work that we do, so it’s positive all around,” he said.

Others at the convention were also working, including a bunch of vendors selling various kinds of sci-fi ephemera, figurines, costumes and other kitsch.

Among them was Andrew Higgins, 26, of Edgewood, a Morgan State University graduate who has a company called A.t.r. Wood Creations, for which he creates custom furniture and wall art. At the convention, he was selling tables covered with the images of X-men characters, cut out of cheap comic books and covered with a clear epoxy.

“It’s a good opportunity for traffic, specifically within the comic and sci-fi realm, to get this sort of esoteric environment for the sort of furnishings we provide,” he said.

Most people at the convention were just fans, though, there for a fun Saturday or a whole weekend of fandom.

Jay Collins, 67, of Long Island, New York, who has been attending Shore Leave for 30 years, said it is all about “people and seeing friends I only get to see once a year.”

Sophie Ashburn, 18, of Louisa, Virginia, was enjoying her first time at the convention with her friend Samuel Brown IV, 19.

“It’s awesome I get to hang out with all other fans,” said Ashburn, who was dressed as a “Star Trek” science officer.

“It’s just fun, plain and simple,” said Paul Richards, 56, of Laurel, a return attendee who was dressed as a lab technician from “Jurassic Park,” complete with a baby velociraptor — a puppet — cracking out of its shell.

“I have a great time every time I come here. The people, the costumes, the vendors,” he said. “It’s just fun.”