At the age of 14 Ansel Adams marched into the great valley of the Yosemite and attacked it, or made love to it, with his box camera. For the next 70 years, roughly, he visited the beautiful spot every year, as seduced with her beauty as when he was a boy, but increasingly a master of the camera and the art of love.

The last five years of his life he worked on choosing among his 40,000 negatives and the thousand best known of those, to arrive finally at the 75 he thought the best, and these he prepared to serve as his eyes long after his death. He lived from 1902 to 1984.

Last night at the National Gallery, which runs more to Duccios than photographers, an exceptional dinner was held in his memory, attended by his widow, Virginia, and his daughter, Anne Helms, and offering a sample of his pictures of mountains and dunes. These photographs were exhibited last night only. A major exhibition of his work will open at the gallery in October, then to be seen in other museums and at colleges, and finally to be given to some institution by Pacific Telesis (a parent corporation for telephone and other companies), which owns them.

Virginia Adams greeted guests in a palm court of limestone columns and ancient tropical plants, the great circular pool fringed with trumpet daffodils and the tables centered with orchids and hundreds of candles.

"I sold my cameras the day I married him," she said, but her daughter, in the way of daughers nowadays, qualified it: "That is not exactly the case."

But for all practical purposes. Really. A mother can scarcely open her mouth today.

A number of capital notables showed up: Secretary of Defense Caspar Weinberger, the recent Democratic candidate for president Walter Mondale, Supreme Court Justice Harry Blackmun, the ambassadors of Austria and China, and Mary Lou Grier, acting director of the National Park Service.

In one of the recent outrages of the capital, a bullet showered glass on Dorothy Blackmun (the justice had just left the living room of their apartment) and it was speculated this might be tied to anger at Blackmun's court opinion supporting the right of women to have abortions.

"I have had no report," he said, "on who might have fired the shot." It was suggested it might have been a clumsy youth inexperienced with firearms.

"If it was a boy, he certainly had a big gun," the justice said.

Grier and others spoke of Ansel Adams as not only a fine photographer and "chief patron of Yosemite," but as a key figure in the increased public interest in nature and the protection of nature during the past quarter-century.

"I was enlightened in his darkroom," said David Brower, chairman of Friends of the Earth, board member of the Sierra Club and a friend for many decades of Adams.

J. Carter Brown, director of the gallery, mixed with the 150 guests and denied rumors that nothing remains in any English country house. The gallery is planning a major show of art from those houses, but he said he did not take everything.

The gallery is preparing a catalogue of the Adams photographs. Peter Bunnell, who holds the McAlpin Chair in the history of photography at Princeton University, said at least 50,000 copies should be run off. Indeed, the room was alive with people not far short of adoring before this photographer's work. They say (as Virgil did of something else) it has a light of its own.

You got to the sampling of the forthcoming full exhibit by walking through two rooms of Havell aquatints of Audubon bird paintings. They are large and full of color, painted from nature in her rich baroque moods. You come to the Adams photographs after all that, and there they are in black and white, not very large, with or without clouds, with or without trees. And they do not look unworthy of a gallery presence.