CAPTION: Picture, Ansel Adams' "Sunrise, Dunes, Death Valley Monuments"

Ansel Adams' 80th-birthday show, now at Harry Lunn's, 406 Seventh St. NW, is a startling exhibit. Its esthetics are familiar--but its economics aren't. The chief laws of art marketing--that he who buys may sell, that rarity increases price--are axioms that grand old man of American photography has turned upside down.

Consider, for example, "Moonrise, Hernandez, New Mexico," his most expensive image--and the most costly photograph by a living artist ever sold at auction. One is here on sale. It costs $18,000. You might think that that means it is extremely rare. But you would be wrong.

Since Adams made its negative in 1941, he has printed it, with care, more than 842 times. And he is printing "Moonrise" still, for each of the 100 "museum sets" he has placed on sale. When, at last, he stops, "Moonrise" will exist in an edition "limited" to 942.

You figure it out. Suppose each print is really worth $18,000. That means that Ansel Adams, with one click of the shutter in 1941, made a golden goose whose golden eggs today have a market value of $16,956,000.

His "museum sets" are beautiful. These one-man retrospectives show him at his best. And they cost a lot. Each contains new prints of 25 old images: 10, common to each set (one of these is "Moonrise"), were selected by the artist; the additional 15 may be chosen, by the purchaser, from a pool of 60. Adams wants these sets to go to universities, museums or other institutions. The individual collector may buy one if he wishes--for $75,000--but only if he pledges that he will never sell it, but, instead, intends to give his set away.

Dealer Harry Lunn, who knows his business well, says that "there are two markets for photography--there is one for Ansel Adams, and one for everybody else."

This is Lunn's fifth Adams show. When the first one opened here, 11 years ago, good prints by the master cost $150 each. "Their prices," Lunn observes, "increased by a factor of nine in the three-year period 1976-1979." They still look terrific. Their details are sharp, their compositions strong, and they still command the wall.

But they are, at least in spirit, not particularly original. Adams is the heir of such 19th-century painters as Bierstadt and Moran, and such 19th-century photographers as Watkins and O'Sullivan, who brought back to the cities detailed, dramatic, often operatic portraits of the storms and mountain majesties of the unspoiled West. Though Adams' prints are beautiful, and beautifully printed, their subject is their secret. He shows us what we want to see. The landscapes that he photographs take the breath away.

His vintage prints on view here seem oddly inexpensive. A handsome seascape made in 1945 costs $4,000; a portrait of Charles Sheeler (circa 1960) is on sale for $3,000; a 1942 image of Zabriskie Point with a most mysterious scale--one is hard pressed to decide if it's a still life or a landscape--costs $3,200. The oldest prints on view are the least expensive. A view of Lower Paradise Valley made in 1927 costs $800. Adams is, at 80, a monument of sorts, a master of his medium--and a master of his market. His exhibition closes April 10.

John McCarty's Sculptures

Most rusted-steel sculptures are so dreary and distressing that the mind tends to shut down at the first glimpse of an I-beam or a Cor-Ten plate. Prejudices bred by scores of pseudo-Tony Caros and pseudo-David Smiths may blind one to the virtues of the art that John McCarty is now showing at Diane Brown's Sculpture Space, 52 O St. NW.

McCarty uses steel scrap, girders, rails, gears, and lengths of rusted boiler-pipe pulled out of the Corcoran. But the sculptures that he makes out of heavy junk are the opposite of junky. They are elegant and subtle, oddly moving works of art.

These human-scaled objects do not sprawl, they stand. Somehow they evoke the ruins of Greek temples more than they do junkyards. Those boiler pipes suggest the flutings of old columns, those folded plates carved draperies, that opening a portal. The Euclidian geometries of their small components, those semicircles, squares and arcs, protect them from the messy. McCarty's steel sculptures are moderate and balanced, handsome and restrained. Their smallest details are interesting, and they work well in the round.

This will be the the last show at the Sculpture Space on O Street. (That wood-floored, brick-walled gallery is to become studios.) Dealer Diane Brown, who has a gallery downtown, says she hopes to open another in Manhattan. McCarty's admirable show closes April 1.

Drawings by Tom Dineen

An oddly kinky image, at once sleek and scary, writhes in the big drawings that Alexandria's Tom Dineen is showing at the Middendorf/Lane Gallery, 2009 Columbia Rd. NW. It looks like a figure, or pieces of a figure, dressed in shiniest black leather, hurtling through space.

Dineen draws superbly, particularly with charcoal, but these pictures don't quite work. Their colors are at fault. Dineen is, at 30, not half as good a colorist as he is a draftsman. The dotted colored fields in which his figures float look as if he put down first one hue, then another, then another and another, but never got it right. Though Dineen is highly gifted, and though his art has elegance, a disturbing contradiction, a battle fought between the pretty and the horrible, diminishes his show. It closes March 27.