ByJames Kaufmann, James Kaufmann reviews books regularly for the Monitor. Even people who don't know much about photography know about Ansel Adams - he's an American institution. Adams's magisterial landscape photographs appear on post cards, posters, and calendarshis new books sell briskly, while his old ones have become collector's items; and virtually every American museum with a photography collection has, or would like to have, at least one of Adams's prints. Adams's fame rests on real achievement. He is one of the finest photographic printmakers of our time, and his books on camera and darkroom technique - ''The Camera,'' ''The Negative,'' and ''The Print,'' all recently revised - are classics of their kind. Now 81, Adams is quite active. ''Examples: The Making of 40 Photographs'' is the latest of his nearly 40 books, and it nimbly treads the line between technical book and monograph. It is, says Adams, a way for him to answer that frequent question: ''How did you make this photograph?'' The photographs whose heritage we learn in ''Examples'' could be labeled Ansel Adams's Greatest Hits, and they are nicely reproduced. Each is accompanied by two to three pages of text, in which history, technique, aesthetic philosophy , and other matters necessary to the realization of the image are discussed. After the story of each photograph comes a list referring the reader to others of Adams's books for a more detailed account, usually technical, of how a given image came to be. Readers not interested in the technique will enjoy ''Examples'' anyway - for its wealth of anecdotes. Perhaps the most useful message in ''Examples'' has to do with equipment. Adams is a master technician, and he necessarily talks about cameras, film, and the like a good deal. It finally becomes clear, however, that - within reason - equipment is relatively unimportant. What is important is that the photographer - at whatever level of skill - understand the technical side of photography well enough not to let it interfere with the making of pictures. But ''Examples'' is also instructive - at times even fascinating - because it reveals a great photographer telling how and why he did what he did.