Frank Jay Haynes (October 28, 1853 – March 10, 1921), known as F. Jay or the Professor to almost all who knew him, was a professional photographer, publisher, and entrepreneur from Minnesota who played a major role in documenting through photographs the settlement and early history of the great Northwest. He became both the official photographer of the Northern Pacific Railway and of Yellowstone National Park as well as operating early transportation concessions in the park. His photographs were widely published in articles, journals, books and turned into stereographs, and postcards in the late 19th and early 20th century.

F. Jay was born in Saline, Michigan on October 28, 1853 to Levi H. Haynes, a merchant and Caroline Oliphant. When he was a small boy, the family moved east to Detroit, Michigan. F. Jay worked in his father's store and took various other odd jobs. As a boy, he had visited the photographic studios of Mrs. Gillette in Detroit and became interested in photography. After several traveling salesman jobs, F. Jay ended up in Ripon, Wisconsin and secured a position as an apprentice in the Doctor William H. Lockwood's Temple of Photography. He worked for Lockwood for 16 months, learned the photography trade and met his future wife, a co-worker, Lily Snyder. In September, 1876 F. Jay left the Lockwood Studio to start his own photographic business in Moorhead, Minnesota with the backing of his brother-in-law, Gus Henderson.

It was in Moorhead that F. Jay began his long and prosperous relationship with the Northern Pacific Railway. A year later, F. Jay's business was booming in Moorhead and in January 1878 he married Lily Snyder in Ripon, Wisconsin and brought her to Moorhead to help with the business. They had a daughter, Bessie Loa and two sons, George and Jack Ellis. Jack Ellis Haynes (1884–1962) inherited his father's business in Yellowstone in 1916 and continued as official park photographer until his death in 1962.