Paul Newman, who had bought tickets, never did shop up for the Actors Studio benefit here Wednesday night - off racing his car in the Midwest reports had it. Also absent, despite advance notice to the contrary, were Robert De Niro (busy in a new movie). Dustin Hoffman (busy in his new movie too), Lynn Redgrave (out of town shooting "Centennial"). Mike Nichols, E. G. Marshall, Julie Newmar and Jill Clayburgh - who had taken a tender ad in the evening's program proclaiming: "I am married to the Actors Studio." (It must be an open marriage.)

That left Al Pacino, who arrived with steady date Marthe Keller, as the evening's most photographed star - an honor he handled thus: He advanced toward the paparazzi glaring, looking almost angry (nobody who is anybody smiles for the camera anymore), went immediately to his table (out of paparazzi range), and he did not mingle a lot.

So the question for Pacino, who spent most of his time talking with 76-year-old Lee Strasberg, the head of the studio, was why had he come to the party?. "I came for Lee."

He did not tell the rest of the story; that years ago when he was an actor nobody ever photographed, he borrowed $50 from the Actors Studio, from the James Dean Memorial Fund. And that recently, he sent the Actors Studio a check for $25,000 to be used for other destitute actors, in memory of an actor friend who died. And that the Actors Studio has trained the likes of Brando, Steiger, Patricia Neal, Shelley Winters and Robert Duvall; and that that afternoon, his old teacher, Strasberg, whose robust young wife does a lot of his talking for him these days, was teaching class as usual.

The things that matter have a habit of never surfacing in mobs, and the studio benefit - held at Manhattan's Roseland Dance Hall off Times Square ("tacky," said one party veteran) - was nothing if not a crowd scene, and not an exciting one.

Billed as a masked ball, the partygoers, who paid $125 a couple to dine and to dance to Peter Duchin, were the anonymous members of the New York theater community who rarely get their pictures in People Vincent Sidey, owner of the restaurant that bears his name, was there, as were Actors Equity and agency representatives, and a lot of people who just like to support theater. There were the loyal Actors Studio old guard: Elia Kazan, Eli Wallach and Anne Jackson, Kevin McCarthy and Harvey Keitel, and Maureen Stapleton, who came late, starring as she is in "The Gin Game."

The entertainment for the benefit was all free. Geoffrey Holder, never a member of the studio, performed a strip in which he did not take off his clothes. Shelley Bruce, the star of "Annie," sand "Tomorrow," the only song anyone can remember from the show. The actresses from the Broadway musical. "The Best Little Whorehouse in Texas," which began as an Actors Studio workshop production, did some song and dance from the show. Joey Adams, the country's official goodwill ambassador, presided as the show's emcee - and said he also had never been a studio member. "Naah, I never took a lesson. I talk for myself, I got my own mumble," he said.