"PHOTOGRAPHY IS still a bit of the stepchild," says Marie Martin, owner of the year-old Martin Gallery, which specializes in contemporary photography, "but it seems to be gaining a lot more credibility."

Photography was long considered the poor relation in the art world, Martin says, perhaps because the images could be readily reproduced. But all that is changing. "A lot of photographers are now limiting their editions, making one-of-a-kind prints. The photographers themselves have realized that they have to make it more special.

"And more people are realizing that something creative -- artistic -- goes on behind the photo before it's taken," she says. "Photography is becoming a major force in the art fields -- you see more and more sculptors and painters turning to photography or incorporating it in some way. People are starting to accept it for what it is. It's an art."

With Harry Lunn's departure after 15 years as Washington's principal photography dealer, the city's photography market has been divided among three young galleries -- Kathleen Ewing Gallery, the brand new Jones-Troyer Gallery, and Martin Gallery. Martin, who was director of Lunn's gallery for five years, just celebrated her first year as a gallery owner. (Incidentally, Martin's gallery, at 3243 P St. NW, once housed Lunn's Georgetown gallery and, after that, Kathleen Ewing's collection.)

Lunn, who now deals privately in art, vintage photography and decorative arts, is in Europe most of the time these days and, according to Martin, "still wheeling and dealing and tracking down wonderful things."

She says that, from her viewpoint, there is a surge of interest in contemporary photography. "People are starting to think that it may be better to get in on the ground floor and start collecting work by new photographers whose work seems particularly strong." Opening Saturday at Martin Gallery is "Sweet silent thought," a series of platinum portraits of 12-year-old girls by Virginia photographer Sally Mann. Martin says the pictures, taken of children in Mann's neighborhood, "capture the balance between being a child and being an adult."

But although she's developed an eye for photography, Martin says she has no natural aptitude for the medium herself. "I can just about load a camera," she says with a laugh.