The lightweight pentax da 50mm f18 lens is a fast prime designed exclusively for pentax k mount digital slr cameras it features a large maximum aperture of f18 and a round diaphragm to ensure a natural beautiful bokeh out of focus effect making it ideal for portraits and snapshots it allows for faster shutter speeds and offers superb handheld low light performance the front of the lens is equipped with sp super protect coating to repel dust water and grease from the surface of the