"Photographers by Photographers," at the Arlington Arts Center, 3550 Wilson Blvd., is part time machine, part party.Because Washington's photographers are forever making snaps of one another, this family album of a group show seems a bit incestuous. But it is also fun. Years glide through these portraits. Lovers meet and part, beards appear and vanish, friendships form and fade.

The camera does not lie. But boy, does it transmogrify. Joyce Tenneson, for instance, when photographed by Arnold Kramer, seems a cornfed farm girl. She is portrayed by Frank Lavelle as a Catholic innocent on her way to First Communion. In Paul Feinberg's spooky portrait she looks more like a witch.

This show whirls along. Almost every picture here leads the viewer to another. The observer who begins by studying the portrait of Mark Power, Allen Appel, Joe Cameron and John Gossage that was made by Shirley True in 1971 will see their faces and their art recur throughout the show.

Power may well be this city's best photographer. He seems much loved by his peers. His kindly and observant face, sometimes bearded, sometimes not, appears in friendly pictures by Cameron and Appel, Pat Dalzell, Frank Herrera, Steve Szabo, Azar Hammond and Frank DiPerna. Szabo also shows us Gossage and DiPerna and his friend. Linda Wheeler, who, in turn shows us Szabo. DiPerna here portrays Cameron and True and his friend, Lynn Allen, who returns the favor. She portrays him bathing; he portrays her in a lovely shot with her arms full of clouds. DiPerna, wearing leathers and looking mucho macho, also shows up in a picture by Jann Darsie. DiPerna, now a fisherman, poses proudly with his catch in a shot by Angie Seckinger. Power, represented here by two portraits of Appel and one of Shirley True, also shoots DiPerna. On and on it goes.

Many of these pictures are less than wholly serious. The photographers portrayed party with each other, lounge about and grin and put on funny hats. A touching and fraternal spirit of affection rules this sometimes jumbled show. It was organized by the Corcoran's Frances Fralin. sShe has included a few shots of photography's celebrities -- Andy Warhol, Walker Evans, Diane Arbus, Lee Friedlander, William Eggleston and Russell Lee -- but the intertwined Alliances of Washington's photographers are the true stars of her show.

Painters, on the whole, are less sociable than photographers. One notable exception is Washington's Charlotte Robinson, who has, for many years, worked at least as hard for other women in the art world as she has for herself. Her generosity has been rewarded. "Hands of Artists," the admirable exhibit of her new pencil drawings, which accompanies "Photographers by Photographers," includes some of the finest and the most accessible work that she has done.

Though Robinson is best known for her large abstractions, these drawings all are portraits, though they do not show us faces, they only show us hands. We see those of Manon Cleary, a cigarette in one, a paint brush in the other, painting a self-portrait, May Stevens' writing notes, Nade Haley's bending wire, and Genna Watson's using tin-snips. The hands of Yvonne Carter, of Maria Da Conceicao, of Rebecca Davenport and of photographer Joyce Tenneson (who appears to be blessing her Olympus 35) are also represented. These drawings all are lovely, rich with light and shadow, thoughtfully composed, but what is more impressive is how accurately they capture the spirit of the art of the artists they portray. Tenneson's hands, for instance, are as soft as her photographs. Cleary's slender fingers suggest the great tension that crackles in her work.

Artists who change styles, who move, for example, from abstraction to representation, often do so quailing. But every graphite shading here, every pencil stroke and cross-hatch, announces self-assurance. Robinson has grown. She has long believed that sisterhood and sharing brings new strength to women artists. Though others may contend that political acticity accomplishes the opposite, drains the artist's energy, her drawings prove her point. The two exhibitions at the Arlington Arts Center support each other nicely. They close June 7.