Standard focal length for 35mm and nice and bright at F1.4 wide open. Beautiful lens to use with the Pentax Takumar Japanese manufacture outstanding. Cared for this lens will last forever and is one you will never regret owning.  Lens is optically clean and cosmetically A grade. You can buy this lens for your M42 screw mount Pentax or choose the option of adding a K&F precision M42-E adapter which enables this lens to be mounted on Sony E-mount, focus peaking cameras. Both lens caps supplied.