The Pentax SF-X was a camera from the Japanese Pentax brand, manufactured by the Asahi Optical Co., Ltd. (called PENTAX Corporation since 2002). It is also known as the Pentax SF-1 in the United States, and was first produced in 1987. It was Pentax's second Autofocus 35mm SLR after the Pentax ME F. It was the world's first AF SLR with built-in auto flash.
The SF-X comes from the same family as the slightly newer Pentax SF7/SF10.
There is a manual available for download at http://butkus.org/chinon/pentax/pentax_sf1/pentax_sf1.htm