IN THE MARCH ISSUE OF DANCE MAGAZINE, there's a list of the readers' choices for the Top 10 dancers of the 20th century. As might be expected, Baryshnikov is number one, but what's incredible — and worth pondering — is that Anna Pavlova comes fourth (after Nureyev and Fonteyn), Nijinsky holds the sixth spot, and Isadora Duncan shares eighth place with Gelsey Kirkland. Three of these dancers were probably never seen in a live performance by the readers who voted for them, who were going strictly by the pictures. Photographs — not videos, though in Duncan's case it could have been films — had planted indelible images in the viewers' minds and, what is most amazing, convinced them they knew what it felt like to see Pavlova, Nijinsky and Duncan in action.

Good photographs of dancers have a powerful, enduring, persuasive effect on the imagination. They are also very hard to find. But now, two small exhibitions of photographs at the J. Paul Getty Museum are showing some of the rarest, along with some of the most famous, images of early-20th-century dancers.

Anna Pavlova loved the camera and was quick to comprehend that her legacy depended on it. Photos of her are usually posed, and if you look closely, her feet have often been inked along the edges to create a more arched and pointed toe. The Getty exhibit “Dance in Photography” (curated by Mikka Gee, Judith Keller and Anne Lyden) contains one unbelievable 1915 photograph by Arnold Genthe in which she is leaping into the air, something few ever attempted in their studies of Pavlova. One leg points straight to the floor; the other crosses in front, bent at the knee, raised like a prancing pony. The miracle is that Pavlova is such an abundant, sexy, energetic woman. We've grown so accustomed to her “dying swan” images — her big, brown, soulful, raccoonlike eyes and a plush white tutu — that to see her arrested midair in sort of a harem dress with her kneecap reaching clear to her breast is strange indeed.

Other curiosities in the exhibit include Edward Weston's closeup of Harald Kreutzberg's hands, and a quaint, delicate self-portrait of the great Imogen Cunningham. The Kreutzberg hands seem to tell the whole story of the body below them, even though you can't see much beyond the forearm. Two fingers rise up through the encircling shape of the opposite palm, and although they definitely appear to be on the verge of weaving in and out, finger over finger, there's only the slightest indication of the motion; one finger is a mere millimeter in advance of the other.

But photographs of dancers tell you that it is only a matter of millimeters. Take, for instance, the well-known Barbara Morgan photograph of a slice of Martha Graham, from shoulder to hip, in Ekstasis (circa 1935). Again, the rhythm of muscle, seen through the vertically ribbed material of Graham's tubular costume, announces the drama and dynamism of her body. But more than that, you can tell by looking at just a portion of Graham that every bit of space around her was meticulously accounted for. One inch this way or that, and an entirely different meaning resulted. She was in control. (And so was Morgan.)

Next door to this exhibition is the collection of Edgar Degas' photographs. Degas took up photography late in life, when he was going blind, and he seems to revel in the mechanics, the solutions, the lighting, the problems of movement and still life, of portraiture and snapshot. The delicacy of a ballerina's shoulder, her small hand reaching for the shoulder strap of her tutu, her anonymity, and the beautiful, rich orange glow of the negative, making the dancers seem as ghosts . . . If anything, these Degas images — in conjunction with those in “Dance in Photography” — make one understand fully why it is possible for significant numbers of Dance magazine readers to trust such photographs. They have, after all, a life of their own.

It is a bizarre lesson, because so much of contemporary dance photography is about catching the impossible: five dancers jumping high in the air, say, and interlocking like an M.C. Escher jigsaw puzzle. But today, one of the greatest mistakes a dance aficionado can make is to conclude, passionately, that a dancer is good on the basis of having seen him or her only in photographs.

The integrity of the dance photograph has utterly changed. For example, three of four significant companies that performed last month in Los Angeles — the National Ballet of Cuba, Meryl Tankard Australian Dance Theatre, Mexico's Taller Coreografico, and Philadanco from Philadelphia — danced nothing like the photos that preceded them. Only the Cubans managed to establish any connection at all between who they think they are, as expressed in press-packet photographs, and what they are onstage. But then, the Cubans are old-fashioned.

IN DANCE, BEING OLD-FASHIONED HAS NOTHING TO do with costumes or scenery or set pieces. The quality of old-fashionedness seems to relate to an extreme consciousness of space as something that can be light or dark, thick and heavy, or thin and light, that has moods — many of the qualities of the Getty's “Dance in Photography” show, in fact. The National Ballet of Cuba fascinated one's eyes with constant modulations of space. Seldom has a corps de ballet in Giselle — choreographed after Coralli and Perrot by artistic director and legend Alicia Alonso — moved in such unison. When they brought out poor Hilarion and hurled him to his death, pointing their fingers, “Go!,” every head wreath, collarbone, arm and finger matched — ping, ping, ping — in a row.

If I had to isolate the precise locus of old-fashionedness in dance, however, I'd say it belongs to the upper arms. The epiphany occurred while watching the Cubans at the Wiltern, during Alihaydée Carreño's mad scene. Later that night, I was in bed reading Martha Graham's memoir, Blood Memory, in which she says something to the effect that the upper arm is the most important part of the body in movement. She's right, and it's all there in the photos.

Graham, we know, was everything that's captured in her photos and more. She was mythic. (There are several more photos by Barbara Morgan at the Getty, and some of them are the inspiration for a performance on the premises on March 12 and 13 by the American Repertory Dance Company.) But if you can't trust today's dance photos, then what exactly will be the legacy of the next generation?

One might guess that the Top 10 list for the 21st century will likely reflect the dancers who have made the most Bulova watch ads. But I think audiences and readers are smarter than that. Photography of dance and photography of dancers are now two separate things, and in most cases both have little connection to the dance that really happens. The old-fashioned days of trusting one's reaction to an 8-by-10 dance glossy are over.

DANCE IN PHOTOGRAPHY and EDGAR DEGAS, PHOTOGRAPHER | At the Getty Center | 1200 Getty Center Drive | Both through March 28

AMERICAN REPERTORY DANCE COMPANY | At the Harold M. Williams Auditorium at the Getty Center | Friday, March 12, 8 p.m., and Saturday, March 13, 2 p.m.

Advertising disclosure: We may receive compensation for some of the links in our stories. Thank you for supporting LA Weekly and our advertisers.