Blow-Up (1966)

Directed by Michelangelo Antonioni, Blow-Up (1966) is a psychological mystery drama set within London’s 1960s fashion scene. Starring David Hemmings and Vanessa Redgrave, the film follows a fashion photographer who becomes obsessed with a series of photographs that may reveal a murder. The film won the Palme d'Or at the Cannes Film Festival and became one of the defining works of 1960s European arthouse cinema. Combining mystery elements with existential themes and surreal ambiguity, it remains one of Antonioni’s most influential films.

Från IMDB:
A fashion photographer unknowingly captures a death on film after following two lovers in a park.