Alfred Stieglitz (1864-1946) was a major photographer, a pioneering gallery owner, a generous collector, a self-appointed cultural commissar and a compulsive polemicist. He was an evangel for photography, insisting that it be recognized as an art, and so he crowed that “The Metropolitan Museum has opened its sacred halls to Photography” when the museum accepted his gift of 22 photographs in 1928. Five years later, he made a further donation of 419 Pictorialist images and, in 1946, a final bequest of 199; these photographs were the start of the museum’s magnificent current collection.

Pictorialism was the fin de siècle style Mr. Stieglitz advocated until he changed his mind and didn’t. It is characterized by soft focus, meaningful shadows, exquisite prints and a sometimes mushy spiritualism. When it works, it creates images of great beauty; when it doesn’t, it seems hokey. The 43 photographs on display include pictures by some of Pictorialism’s great practitioners: Gertrude Käsebier, Alvin Langdon Coburn, Edward Steichen, F. Holland Day, Clarence H. White and Adolf de Meyer. About a quarter of the pictures are portraits of artists; see, for instance, Mr. Day’s 1896 study of Kahlil Gibran, the kitschy mystic, or Frank Eugene’s 1907 portrait of Mr. Stieglitz with his showy mustache. There are many pictures of Nature, mostly aestheticized. My favorite is Frederick H. Evans’s “In Deerleap Woods—A Haunt of George Meredith” (1909); the delicate platinum print has the illusion of depth that enhances the tree at the center of this simple image.

Johann Wolfgang von Goethe was a poet, storyteller and traveler whose 1,400-page treatise “Theory of Colors” (1810) furnished Alex Webb his epigraph, “Colors are the deeds and suffering of light.” Like Goethe, Mr. Webb is besotted with color, one of the few photographers in whose work color is not just additive, but integrally constitutive. Like Goethe, Mr. Webb can use his medium for either narrative or poetic ends, and he too is a traveler, frequently to places in hot climates where bad things happen. The 52 pictures at Aperture include work from three decades, beginning with the dreamlike “Boquillas, Mexico” (1979), in which the only figure is a young man who seems to be levitating in a deserted town of pastel yellow and pink buildings, to “Erie, Pennsylvania” (2010), in which we see children in a wading pool through the scrim of a rainbow.

Mr. Webb shoots scenes that are teetering on the brink of chaos from which they are just barely rescued by his decisive compositions. There is a tacky portrait of Jesus with his crown of thorns in the center foreground of “Tijuana, Mexico” (1999). A poster of Santa Claus in his sleigh lies on its side in the upper left, the comely legs of a girl emerge from the shadows in the upper right, and some teenage boys seem to be larking in the lower left. Incredibly, Mr. Webb makes this jumble work.

Piscinão de Ramos, its name in Portuguese, is an artificial salt-water lake located in a vast area of favelas(shantytowns) in Rio de Janeiro. This is a rough neighborhood; the surrounding favelas are controlled by competing drug gangs. Still, the Ramos swimming pool is mostly free of violence, and an important recreational facility for people distant geographically and socially from the upscale scene at Ipanema. Julio Bittencourt, one of Brazil’s talented young photographers, spent much of 2008 shooting people on the beach and in the water at Ramos, and 11 of his large- format digital c-prints are up at the 1500 Gallery, a venue dedicated to Brazilian photography.

Mr. Bittencourt revels in the dark and ample flesh of the bathers. We see the woman in “Ramos 02” (2008) only from the neck down. She sits in a beach chair wearing a skimpy bikini, her brown skin slathered with a white lotion; next to her chair is a bright yellow beach towel imprinted with the statue of Christ the Redeemer on Sugarloaf Mountain. The woman in “Ramos 11” (2008) is also headless; Mr. Bittencourt does not focus on her bikini top, which just barely maintains her modesty, but on a Styrofoam tray balanced on her thighs heaped with a dish of meat and rice. In “Ramos 35” (2008) two young women wearing the de rigueur skimpy bikinis lie in shallow water with their eyes shut as they soak up the Brazilian sun.