Although he died in relative obscurity in 1952, Edward Curtis left behind a legacy of 1,500 photographic images declared to be the single most comprehensive glimpse of native Americans. Curtis spent 30 of his 84 years shooting and publishing a $3,000, 20-volume work on the history, life and habits of the North American Indian.

Yet even with a $75,000 loan from J.P. Morgan, the project was a financial failure: Only 240 of a projected 750 sets of the books were published, and many of them gathered dust until the counterculture of the '60s adopted one of Curtis' portraits as a poster image of solidarity and defiance. Soon after that, a monograph appeared touting Curtis' visual genius. Individual plates removed from the books began to sell briskly for several hundred dollars apiece, and recently a complete set of "The North American Indian" brought $73,000 at auction.

A new photo show, which opens today and runs through April 15 at the Smithsonian's Museum of Natural History, takes issue with the image of the American Indian portrayed by Curtis. Curated by Christopher Lyman, who has just written a book called "The Vanishing Race and Other Illusions," the exhibit advances the thesis that anyone as prejudiced toward Indians as Curtis admittedly was couldn't possibly have made images that portrayed native Americans in a positive let alone accurate light.

To demonstrate his theory, Lyman trots out photo after photo in which Curtis provided the headdress, airbrushed out cars and suspenders, and arranged his subjects in nonflattering settings. All well and good--but somehow it smacks of judging the art by the artist (and we're not dealing with conceptual art here). The issue seems to belong more in the philosopher's classroom than in the overview of a large, general-audience museum. Were Leni Riefenstahl's films bad because she was a Nazi?

Lyman's criticism is more specific: Curtis wasn't documenting a way of life; he was creating or, better yet, re-creating one to fit his own stereotyped vision of the Indian. Yet that seems in some sense the very nature of art: The works of Diane Arbus and Andy Warhol are distortions of reality, and precisely for that reason they document their age.

A further quibble of Lyman's is that Curtis doctored some of his prints to remove, for example, an alarm clock from the background of a teepee. In fact, at the turn of the century (a few decades after the invention of photography) it was common practice to alter details in an image. The initial tradition of photography was as a tool to aid painters, and in later years photographers often adapted certain pictorialist traditions to their art.

In the end, a photograph stands as a visual image and, notwithstanding his attitudes about Indians, Curtis' photos still seem to be striking frames of land and people--however real or constructed they are. This show fails to present the work in a context that allows the images to be judged on their own merits.