The Metropolitan Museum of Art scored big with some critics this summer with "The Pictures Generation: 1974-1984," a rare foray by the institution into trends shaping the current art world. Although the show featured work made decades ago by John Baldessari, Barbara Kruger, Cindy Sherman and Richard Prince, among others, many of these artists — not to mention their legions of students — are still actively working and showing today. And the winking appropriation art, self-reflexive media critiques and witty photo-based conceptual strategies they popularized still dominate the art scene.

But the members of the Pictures Generation — so called after a 1977 Artists Space exhibition curated by Douglas Crimp and his 1979 October magazine essay of the same name — created another, knottier legacy that is still with us 30 years later. While they succeeded in infiltrating the mainstream, they also helped to carve a great divide between photo-based artists and photographers that integrates the former into the contemporary art elite and ghettoizes the latter.

Photo-based artists, who often identify themselves as "artists who use photography as a tool," get shows at Gagosian and Barbara Gladstone and win Golden Lions at the Venice Biennale. They have become unlikely market darlings, celebrated despite the apparent unoriginality of some of their work and showcased at the most important art fairs. Photographers who don’t distance themselves from their medium — or deny their darkroom experience! — are exhibited at smaller, specialized galleries. As a result, even figures as big as Sally Mann and Richard Misrach are left out of international art events and shortchanged at the major fairs.

Photo-based artists tend to make one-of-a-kind pieces so that their work, however ironically, approaches painting in originality and singularity, if not quite price. Photographers tend to work in large editions with affordable price tags.

Photo-based artists fit comfortably into contemporary collections, alongside conceptual-leaning types ranging from Andy Warhol to Jeff Koons. Photographers today belong in historic lens-based collections next to other shooters, from Walker Evans to William Eggleston.

Photo-based artists are considered innovative, intelligent and relevant. Photographers are considered conventional, workmanlike and even — to borrow a French phrase — "as dumb as a painter."

I’ll stop there. I’m sure you’ve found several exceptions to these rules already, proof that I am sketching in broad strokes. But the persistent prejudice against photography in the contemporary art world is so rarely acknowledged these days that I decided to take some rhetorical license to try to bring it into relief.

A clear example of that bias can be found in the antiphotography statements made by Wolfgang Tillmans. Tillmans would not have a five-star hotel to sleep in or celebrity friends to shoot were it not for the invention of the still camera, yet he insists in interviews that he is an "artist who uses photography" and not a "photographer."

You can see his reasoning. Tillmans is interested in installations, not individual shots. And his photography is nontraditional in its choice of subjects and unconventional in its composition and lighting. But so were the pictures of Alfred Stieglitz in his day and of Diane Arbus in hers. They were not afraid to call themselves photographers. Why is Tillmans?

The cynical answer is that Tillmans is positioning himself to claim the sexier art-historical lineage of photo-based art — and its higher prices. More simply, he is distancing himself from a medium that many contemporary-art collectors and dealers dismiss or just don’t get, perhaps because it can never quite sever its ties with reality and realism.

Tillmans is not alone. Many photo-based artists are photographers, if you consider their ongoing exploration of the medium. To say otherwise is to strip the history of photography of one of its most interesting and fruitful developments. But certain critics and artists are determined to do just that.