Opteka High Definition 500mm / 1000mm f/8 Preset Telephoto 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 f/8, High-index / low-dispersion optical glass, Fully multi-coated, every element, Anti-reflection coating Designed to maximize day and night shots by providing maximum light and image transmission with minimum distortion, Fantastic for all types of photographic situations Great for the wildlife or nature photographer who wants to be hidden while taking photos of the subject 500mm Preset Lens, Carrying bag, and lens caps included! May be combined with the Opteka 2X Multiplier for 1000mm Zoom (Sold separately - 47st Photo Item Code: B000JSZ41S)