The Pentax Asahi Super-Takumar 55mm F/1.8 lens is a high-quality, fixed/prime lens designed for portrait and standard photography. It has a maximum aperture of f/1.8, allowing for excellent low-light performance and shallow depth of field. The lens is compatible with Pentax cameras and has an M42 mount. The exterior is made of brass and the lens is manufactured in Japan. It comes with a compatible lens front of 49mm and compatible filter size of 49mm.