Helmut Gernsheim, a one-time commercial photographer who helped create the academic study of the history of photography, became one of its most influential and prolific practitioners and assembled one of the most extensive private collections of early photographs, died on July 20 in Switzerland. He was 82 and lived in Lugano, Switzerland.

When Mr. Gernsheim turned from taking pictures to studying the history of photography in London in 1945, photography was not taken seriously as either art or acamemic study. Although Beaumont Newhall had presented a groundbreaking exhibition at the Museum of Modern Art in New York in 1937, there were still no galleries devoted to photography and no photographic auctions.

Over the next 25 years, Mr. Gernsheim and his first wife, Alison Eames, virtually created the field, carrying out extensive research in private libraries and dusty attics and writing both the syllabus and the texts used by later historians.

Their monumental works, "The History of Photography" (1955) and its derivative "A Concise History of Photography" (1965), are still regarded as the authoritative reference works. Their studies of individual 19th-century photographers from Joseph Nicephore Niepce and Louis Daguerre to Lewis Carroll set the standard for later scholars, and their photographic histories of Sir Winston Churchill, Queen Victoria and others extended their work to a popular audience.

A native of Munich, Germany, who trained as a photographer there before fleeing the Nazis, Mr. Gernsheim set up shop as a commercial photographer in London in 1937. After the outbreak of World War II he was interned as a "friendly enemy alien," and transported to a bleak detention camp in Australia where he whiled away his time lecturing his fellow inmates on the esthetics of photography.

He won a return to London in 1942 by volunteering for a macabre assignment, making a photographic record of London landmarks that might be destroyed in the war.

Within months of his return he published a monograph based on his Australian lectures, in which he derided the "antiquated, fuzzy, sentimental, sugary work" that passed for photographic art in wartime London.

The monograph brought him to the attention of Mr. Newhall, by then the curator of the Museum of Modern Art's new department of photography, and when Mr. Newhall went to London to visit him in 1944, the meeting changed Mr. Gersheim's life.

Arguing that British photography would reform itself without further intervention from Mr. Gernsheim, Mr. Newhall urged him instead to devote himself to collecting and preserving distinguished 19th-century images, which were in danger of being lost forever. Taking the advice, the Gernsheims began collecting. It was a measure of the low regard in which photography was held at the time that they quickly assembled some 6,000 photographs with virtually no outlay.

By far their most significant find was the discovery of a long-lost pewter print made by Niepce in France in 1826 or 1827, more than a decade before the first daguerreotype in 1839, which had long been considered the beginning of photography.

Although his extensive writings, including 26 books, and various exhibitions won critical praise and helped change attitudes toward photography, progress was slow. That became apparent in 1961, when Mr. Gernsheim, who had become a British citizen in 1946 and had long dreamed of finding a permanent home for his collection in Britain, showed his collection on television in what amounted to an infomercial seeking benefactors for a British photographic museum.

No British benefactors came forward, and two years later, the entire Gernsheim collection of some 50,000 images, 3,000 books and albums and 300 pieces of equipment was bought by the Harry Ramson Humanities Research Center at the University of Texas, which overnight became one of the world's premier photographic repositories, rivaled only by the International Museum of Photography and Film in Rochester.

Although no price was disclosed, Mr. Gernsheim indicated he had received less than $500,000, enough to pay for his retirement in Switzerland, but, the collection's senior curator, Roy Flukinger, said that was only a small fraction of what it would have fetched a decade later when the market Mr. Gernsheim helped create came of age.

Mr. Gernsheim, who remarried after his first wife's death in 1969, is survived by his wife, Irene.