About two-thirds of the way through “First Seen: Photographs of the World’s Peoples,1840-80” is a picture of George Sand, an albumen paper print taken by Andre Adolphe Eugene Disderi around 1860. Sand sits astraddle her chair, one arm draped on the top of its back, the other resting on her knee and holding a cigarette. She wears the clothes of a Parisian dandy – a well-cut coat, a weskit, cream-colored pants with a stripe down the side, a flamboyant cravat – and stares insouciantly at M. Disderi and us, letting us know that even if it is not her manipulating the photographic equipment, she is in charge of the shoot.

Among so many strangers, George Sand seems welcomingly familiar. “First Seen” features 250 portraits from the Wilson Centre of Photography, which has tens of thousands of pictures collected by Michael Wilson from the earliest decades of photography, when the processes invented and announced almost simultaneously in Paris and London quickly circled the globe.When the Westerners who established portrait studios in India, China, Japan, South America, and elsewhere retired or moved on, indigenous apprentices soon mastered the technology necessary to take charge.

Kathleen Stewart Howe has curated the exhibition with great intelligence, avoiding politically correct multicultural cliches with a broad understanding of these first encounters between people no longer separated by geography, but by a lens. The show includes pictures of Mexicans, Koreans, Borneans, Chinese, Mozambicans, Andamanese, Native Americans, Russians, Tasmanians, Lepchas, Japanese, Italians, Tibetans, Pathans, Lapps, Persians, Patagonians, Malagasy, and Singalhese – also Englishmen bent upon empire and Scots in kilts. For several of these peoples, for instance the Koreans, these were the first photographs ever taken of them.

The show is something like stumbling upon an enormous pile of old National Geographics in the attic; we are hauled from place to place and introduced to people in an ethnographic kaleidoscope. That was why the picture of George Sand seems stabilizing: ah, a sophisticated Westerner, one of us. But Sand is a woman dressed in men’s clothing, certainly not typical of mid-19th century French dress habits, maybe only of a very, very small Bohemian stratum of intellectuals and artists. No one today would deny her choice of couture, but since we know her, and her defiant disregard for convention, we know it is a picture of George Sand we are looking at, and not a picture of some generic Frenchwoman.

But, then, we have to realize that all the portraits on the walls are of individuals, and even though most of them are not identified by name and are probably more typical of the peoples from whom they come than is Sand, each has his inscrutable destiny. Like so much late 19th-century portraiture, these pictures tend to have a strong sense of character. But “identity” keeps slip-sliding away.

The four “Tasmanian Aborigines” (c. 1878) by an anonymous photographer are no more dressed in native outfits than is Sand. The three women wear multilayered formal Victorian dresses and elaborate headgear, the man a wide collared coat and highly polished shoes. The black faces stare at the camera with stoic determination. Keith Windschuttle, the Australian historian, has convincingly argued that the native population of Tasmania was wiped out by diseases beyond anyone’s control, not by the genocidal impulses of settlers, and here is this doomed quartet posing in frippery. Would the picture – would they – somehow be more authentic if they wore what their forbearers wore before the first white man landed?

Still, a large part of the pleasure of the show is to see native peoples in what we are expected to believe are their native costumes. The “Burmese Lady” (c. 1870), with her fan and several ornate fabrics, is elegant. Roger Fenton’s “Discussion Between Two Croats” (c. 1855), shows the men dressed as if for a Balkan operetta. The two men in “Spanish Costumes” (1854), by Jean-Jacques Heilman, are from another operetta. Ditto the “Piferrari, Itinerant Italian Musician” (c. 1860). It is interesting how many of the pictures are of musicians with their exotic instruments, and how unfortunate we cannot hear them. It is also interesting how women who strike us as beautiful – and there are several here – seem to transcend ethnicity.

This is not the homogenized humanity of Edward Steichen’s “Family of Man,” in which all differences are superficial, and everyone – when you get to know him – is basically the same as you and me. Many of the pictures in “First Seen” are group photos. The most striking of these is Felice Beato’s “Crucifixion and Gokumon” (c. 1875), taken in Japan. The crucified man hangs heavily from a double cross, his wrists and ankles tied to horizontal beams, his head resting on his shoulder. In the foreground is a wooden frame on which sit three severed heads, quite serene considering how violently they must have died. The pictures of Chinese women with itsy-bitsy bound feet are another example that different cultures do different things at different times; so, too, the occasional pictures of slaves.

When I was an undergraduate at the University of Pennsylvania in the late 1950s, I took a course in the philosophy of the social sciences with William Fontaine, the first black man to teach in the philosophy department. He was a tall, thin man, neatly turned out, with a wry sense of humor that the class mostly failed to appreciate. When we came to the problems of ethnography, he tried passionately to make us understand the difficulties of cross-cultural representation, how hard it is – perhaps impossible – for people in one culture to truly understand people in another. But how necessary.

At that time Fontaine was advising the little-known Martin Luther King on strategies that might convince unsympathetic whites to accede to black calls for equality. I thought of Dr. Fontaine at this exhibition, as I thought of him when I saw women in black burqas casting their ballots in Iraq.

Until May 1 (580 Madison Avenue, at 56th Street, 212-759-0606).