Apurba Kishore Bir, also known as A. K. Bir, is an Indian film cinematographer, screenwriter and director. An alumnus of the Film and Television Institute of India, Pune, he worked in various Ad-films and documentaries before making his feature-film debut. He won the National Film Award for Best Cinematography for 27 Down, his debut film. His directional debut Aadi Mimansa won the Nargis Dutt Award for Best Feature Film on National Integration. Bir's other directional ventures Lavanya Preeti and Baaja were bestowed with the National Film Award for Best Children's Film. As of 2014, he has won nine National Film Awards—including three for Best Cinematography—and is one of the directors of National Film Development Corporation of India.

27 Down is a 1974 Indian drama film directed by Awtar Krishna Kaul, starring Raakhee and M.K. Raina. The film is based on the Hindi novel Athara Sooraj Ke Paudhe, by Ramesh Bakshi, about a railways employee who meets a girl on the train. The film's music was performed by classical musicians Hariprasad Chaurasia and Bhubaneswar Mishra, while the production design was by Bansi Chandragupta.