There’s more than one answer to the question “What is photography?,” and this fall in London, there are a dazzling array of possibilities on show in retrospectives of the Japanese artists Hiroshi Sugimoto and Daido Moriyama.

Born 10 years apart (Moriyama in 1938, in Osaka, and Sugimoto in 1948, in Tokyo), both photographers came of age in Japan’s postwar photography boom. During this time of political change and technological innovation, practitioners explored, and frequently critiqued, the photograph as journalistic document, art object and mass media advertisement. Photo books and photography magazines proliferated, as did connections with American art scenes including Minimalism, Pop and the grainy realism of street photography.

Both photographers are also invested in the more ephemeral, even metaphysical, qualities of the medium: How it freezes or reconstitutes time, brings the dead or the inanimate to life, unsettles concepts of memory, reality and vision itself. If these questions unite Moriyama (whose London show runs at the Hayward Gallery, through Jan. 7, 2024) and Sugimoto (at the Photographers’ Gallery, through Feb. 27) their many-decade oeuvres could scarcely be more different.

“All my life I have made a habit of never believing my eyes,” Sugimoto has said. Across four floors of the Hayward’s stark, Brutalist galleries, nine black-and-white series spanning 1976-2022 are staged in austere displays. Each body of work addresses the seen and the unseen, exterior and interior life, with deceptive simplicity.

A sequence of “Diorama” photographs, begun shortly after Sugimoto arrived in New York in 1974, capture scenes from the American Museum of Natural History with otherworldly precision. Using an old, large-format camera, long exposure times and elaborately tuned lighting, Sugimoto enhanced both the artifice and the verisimilitude of the institution’s taxidermy wildlife tableaus behind glass.

“Polar Bear” (1976) shows the majestic white animal roaring over a fresh kill: the bloodied body of a seal whose inert form is bulky and dark against an Arctic white background that stretches into the distance. Look closely and behind the bear — with its luscious coat of fur, its big paws so heavy in the snow you can almost hear it crunch — the line between two and three dimensions is just visible: a jagged crevasse in the ice floe beneath the two animals merges almost seamlessly with a painted backdrop of receding icy peaks.

The eye judders between these realities. The dead bear, momentarily brought to life by the vividness of the photograph, dies again, and is preserved again, a copy of a copy, frozen between past and present. Similar fates await a pair of ostriches defending their new hatchlings against a family of wart hogs (“Ostrich-Wart Hog,” 1980) and a placidly floating mother manatee and her calf (“Manatee,” 1994).

Sugimoto’s play with photographic abstraction is evident in a series of “Seascapes,” dominated by long horizons and blank skies, “Lighting Fields” produced with bolts of electricity sent across sheets of unexposed film and rich chromatic studies (“Opticks”) made by shining light through a prism demonstrate Sugimoto’s play with abstraction. But it’s the “Theaters” series, arguably his most famous, that maintains the most beguiling promise of photography to capture a flickering in-between state.

In cinemas, drive-ins and abandoned palace-style theaters across the United States (and sometimes Europe), Sugimoto set his camera’s exposure time to the length of a movie screening. His device sees what no naked human eye can apprehend: a bright white vortex of time elapsed, frame upon frame upon frame, at once stilled and in motion. In Massachusetts, Indiana, New York, Philadelphia, the shadowy rows of seats, crumpled velvet curtains and decorative wall moldings are irradiated by a central focus that is not an image but a light so bright and uncontainable that its edges are smudged like a ghost.

Across town at the Photographer’s Gallery, also unfolding across four floors, the Moriyama retrospective does away with any sense of the photograph as a rarefied art object. Where Sugimoto’s images are clear, large, refined, singular and precious, Moriyama’s are multiple, democratic, immersive, rapid and haphazard, and varied in size, material and presentation.

“When people realize that the time they supposedly live through actually has no substance,” Moriyama has said, “they tend to be seized with fear and an unspeakable apprehension about the excessive uncertainty of it all.” In the end, he added, “human existence has essentially nothing to rely on.” Displayed on wallpaper, in grids, projections, photocopies, conceptual assemblages, contact sheets and books, his work embraces the dark flux of life that cannot be contained, but must somehow be preserved.

Moriyama’s subjects are accidents, political conflict, urban ennui, loneliness, cheap commercial goods, all the details of the everyday — as many as possible — caught in passing and printed in high-contrast black-and-white. Rakish angles, extreme close-ups, blurred fragments and decentered, deliberately awkward cropping dominate the profusion of images arranged in nonlinear displays that leave interpretation to the viewer: an open mouth, a movie theater marquee, a boy playing with a ball, Lyndon B. Johnson on a television screen, a crowd of police in the night, a black cat in a hallway.

In his 1969 “Accident” series, chaotic combinations scramble perspective while also taking aim at the omnipresence of mainstream media sensationalism. Later series are more intimate and melancholy. “Farewell Photography” (1972) brings together images that might usually be considered errors — grainy, blurry, out-of-focus (are, bure, boke in Japanese) — to dismantle photographic expectations of clarity and truth.

In “Memories of a Dog” (1982), made during a period of creative crisis, Moriyama revisits locations of his peripatetic childhood in search of scenes that reflected his current interior state: scrolls of film, a hand against the sky, a cherry tree in blossom — as if photography were a form of time-travel, bridging the rift between past and present.

What world does a photograph show? Is it a record or a work of art? As Moriyama wondered, “What is the work that unites light, time and the visible world?” In these two exhibitions, which encourage slow, careful, sometimes rapturous looking, there is — refreshingly — no need for an answer.