Yoichi R. Okamoto, 69, official White House photographer during the presidency of Lyndon B. Johnson, died April 24 at his home in Bethesda. A spokesman for the Montgomery County police said Mr. Okamoto's death was ruled a suicide by hanging.

Mr. Okamoto, former chief of the visual materials branch of the U.S. Information Agency, met Johnson in 1961 when he was assigned to photograph the then vice president on his visit to the Berlin Wall.

Pleased with Mr. Okamoto's work, Johnson invited him to accompany him on several other overseas trips when he was vice president, then made him White House photographer when he became president after the assassination of President John F. Kennedy.

Upon the expiration of the Johnson presidency, Mr. Okamoto formed Image Inc., a Washington custom photo lab that he operated until he retired early in the 1980s. He also had done free-lance photography since leaving the White House.

Mr. Okamoto was born in Yonkers, N.Y., and graduated from Colgate University. He served in the Army in Europe during World War II and for part of that time was the official photographer of Gen. Mark Clark. He worked as a photographer on a newspaper in Syracuse, N.Y., and served in USIA posts in Germany and Austria before moving to the Washington area in the mid-1950s.

Before being assigned to photograph vice presidential overseas trips, Mr. Okamoto traveled extensively throughout the world lecturing on photojournalism. As White House photographer, he was sometimes known as the president's "shadow" and was given access to photograph the president in situations that were off limits to other photographers.

Mr. Okamoto had won several photographic awards, and his photographs appeared in Edward Steichen's "The Family of Man" exhibition.

Survivors include his wife, Paula, of Bethesda; a daughter, Karin Wartofsky of Washington; a son, Philip, of Greenville, S.C., and three grandchildren.