Opteka 500mm f/8 High Definition Telephoto Mirror Lens for Pentax K-S1, K-500, K-50, K-30, K5 IIs, K-7, K-5, K-3, K-2, K-X, K20D, K100D, K110D and K10D Digital SLR Cameras Type: Telephoto Lens Focal Length: 500 mm Camera Mount: Pentax K Aperture: Maximum: f/8 Minimum: f/16 Diameter: 72 Focus Type: Manual Focus Minimum Focus Distance: 5.6 feet Parts: 10 |