The Pentax Super Takumar 135mm f3.5 M42 Prime lens is a high-quality telephoto lens with a manual focus type. It is compatible with various camera brands such as Canon, Four Thirds, Sigma, Sony, Fujifilm, Lumix, Pentax, Nikon, and Leica. The lens is part of the Pentax Super-Takumar series and has a maximum aperture of f/3.5. It is also compatible with a 49mm filter size and is suitable for full-frame cameras. Additionally, it is mirrorless compatible.