The Pentax 645N is an autofocus medium format SLR film camera released by Pentax in Japan on December 6, 1997, and introduced in the US in February 1998. It is based on the earlier manual focus Pentax 645 model, inheriting its basic design concept. The 645N was the first medium format autofocus SLR system available, utilizing the Pentax SAFOX IV phase-matching predictive autofocus system. It features automatic film advance with a motor drive and is compatible with Pentax-FA (autofocus) and Pentax-A (manual focus) lenses. The camera is powered by 6x AA batteries.