The Pentax 645 is a medium format film camera that was first introduced in 1984. It is part of the Pentax 645 system, which includes a range of lenses and accessories. The camera features a 6x4.5 cm format, which is larger than the standard 35mm format, resulting in higher resolution and image quality. It has a sturdy and ergonomic design, with a built-in motor drive for advanced functionality. The Pentax 645 offers a variety of exposure modes, including aperture priority, shutter priority, and manual mode, giving photographers full control over their images. It also has a TTL metering system for accurate exposure measurement. With its interchangeable lenses and versatile features, the Pentax 645 is a popular choice among professional photographers and enthusiasts who want to explore the world of medium format photography.