A leading member of the expert team that declared that a box of negatives bought at a California garage sale were the lost work of Ansel Adams has changed his mind.

Robert C. Moeller III, a former curator at the Museum of Fine Arts, Boston, and one of the experts hired by Rick Norsigian, a California man, to evaluate his find, said that after further review he had decided that at least some of the images Mr. Norsigian purchased were taken by an unheralded photographer, Earl Brooks.

“I made a mistake,” said Mr. Moeller, a former curator of European decorative arts and sculpture at the Boston museum, who was part of the team that in July announced the discovery of what it called Adams’s “lost negatives.”

Mr. Moeller said that his reversal last week came after examining four pictures owned by Marian Walton, of Oakland, Calif., a niece of Mr. Brooks’s. Ms. Walton has said that her uncle took at least one of the photos that Mr. Norsigian and his team have represented as the work of Adams. When Mr. Moeller reviewed additional high-resolution images of Mr. Brooks’s images, all landscape shots of Yosemite National Park thought to be taken in the 1920s, he agreed.