The Asphyx - (Sci Fi / Horror) - 1972

Also known as The Horror of Death,
'Hugo Cunningham is a brilliant turn-of-the-century scientist, loved and respected by his family and friends, admired by his colleagues. But he is a man becoming obsessed with a frightening question. 'What happens at the moment of death?'. What is the mysterious apparition, found in the photographs he takes, of people who are about to die ?"