Cunha started his professional career in 1970, initially related to publicity. He was first a collaborator of the newspaper "Notícias da Amadora", in 1971, moving to the more prestiged weekly "O Século" and his magazine "O Século Ilustrado", in 1972. He was one of the main photographers of the revolution of 25 April 1974, capturing some of the most memorable images of the historical event. He also documented the Decolonization, capturing the return of many Portuguese who came back from the African colonies, in 1975. He worked for three Portuguese news agencies, the ANOP, since 1977, the Notícias de Portugal ("News of Portugal"), since 1982, and LUSA, created as the merger of the two previous, in 1987.