The eminent photographer was born in Dalton, Northumberland, the son of an industrialist. He married the novelist and artist Jennifer Lash in 1962. Their six children included the actors Ralph and Joseph Fiennes.
Mark Fiennes only took up photography professionally in 1969. His later commissions included the catalogue for the Treasure Houses of Britain exhibition in 1985, and he documented the restoration of the state rooms in Windsor Castle for the royal collections. He recorded many gardens and photographed the John Soane museum in London for its bicentenary. According to Peter Somerville-Large, Fiennes was a perfectionist: 'He never jeopardised his high standards with the problems of making a living. He took his photographs infinitely carefully and slowly, bringing to them an unusual clarity and that greatest of assets, and artist's eye.'