THE NATIONAL Gallery of Art, to quote Sarah Greenough, curator and head of the museum's department of photography, is nothing if not "deliberate and careful" when it comes to making decisions about what to show and how to show it. It is therefore appropriate, not to mention unsurprising, that "All the Mighty World: The Photographs of Roger Fenton, 1852-1860," the exhibition chosen to inaugurate its new galleries dedicated to photography, should showcase someone like its subject.

Chances are you haven't heard of him. If you have, it's probably for his pictures documenting -- with extreme decorum, mind you -- the Crimean War. Less well known are his photographs of clouds, English country landscapes, still lifes, members of the British royal family, stately buildings and staged Orientalist tableaux. It is in one of these latter pictures, however, the 1858 "Pasha and Bayadere" (depicting a turbaned Fenton sitting by an unlit hookah), that the phrase "deliberate and careful" is in full flower. How else to explain the quite visible wires the photographer had to use to hold up the heavy-looking arms of the phony "dancing girl," who seems on the verge of falling asleep?

In fairness, the wires were necessary to hold Fenton's subject still for the medium's long exposure times (hence Fenton's affinity for buildings like the British House of Parliament, which doesn't move). It should also be pointed out that the photographer's contemporaries also criticized the "Pasha" image for the same reasons it looks stiff to us.

In other ways, Fenton's innovations are more visible. His cloudscapes, for instance -- exposed to highlight the drama of the sky at the risk of leaving the landscapes in shadow -- feel strikingly modern, as does the close-up of an archery target. It should be noted that this last image, taken after Queen Victoria had achieved several near-bull's-eyes from a pre-aimed, tripod-mounted bow, is, for all its Jasper Johnsian prescience, still little more than a canned photo op for the monarch.

But enough about Fenton.

The real news is that, by opening these handsomely refurbished galleries, the National Gallery has finally acknowledged the importance -- and permanence -- of photography in art history. In the relatively short amount of time that the institution has been actively collecting photos (a separate department wasn't established until 1990), the permanent collection has grown from fewer than 2,000 pictures by a mere two photographers (Alfred Stieglitz and Ansel Adams) to more than 8,000 works by some 180 artists. By contrast, the Corcoran Gallery of Art owns about 5,000 photographs.

Upcoming shows, which will be divided between exhibitors drawn from the collection and a roster of special exhibitions, will include next year's "Andre Kertesz," highlighting the work of the influential and innovative Hungarian American artist known for his sense of urban poetry.

"All the Mighty World" isn't the first or the most cutting-edge photo show the National Gallery has ever mounted, but as a demonstration of the museum's commitment to the medium, it suggests, as Humphrey Bogart said in "Casablanca," the beginning of a beautiful friendship.

ALL THE MIGHTY WORLD: THE PHOTOGRAPHS OF ROGER FENTON, 1852-1860 -- Through Jan. 2 at the National Gallery of Art, West Building, Fourth Street and Constitution Avenue NW (Metro: Archives/Navy Memorial). 202-737-4215 (TDD: 202-842-6176). www.nga.gov. Open Monday-Saturday 10 to 5; Sundays from 11 to 6. Free.

Public programs associated with the exhibition include:

Dec. 10 at noon; Dec. 13, 15, 21 and 23 at 1; and Dec. 17 at 2 -- Gallery talk.

November -- The National Gallery will present the British television series "The English Garden," narrated by John Gielgud. Parts 1 and 2 screen Nov. 3-5; parts 3 and 4 on Nov. 10-12; and parts 5 and 6 on Nov. 17-19. All screenings take place at 12:30 in the East Building large auditorium.

Photographer Roger Fenton used wires to hold up the "dancing girl's" arms because of long exposure times in his photo "Pasha and Bayadere."