The Pentax SMC Pentax Fish-Eye 17mm f4 MF K Mount Diagonal Fisheye Lens from Japan is a unique and high-quality lens designed for Pentax cameras. With a maximum aperture of f/4, this lens allows for a shallow depth of field and creative visual effects. It features manual focus, a metal exterior, and comes with a genuine metal front and rear cap. The fisheye design provides a distinctive perspective, making it ideal for capturing artistic and creative shots. Compatible with a 58mm filter size, this lens is a versatile and reliable choice for photographers looking to add a creative touch to their work.