The Rokinon 16mm f/2.0 ED AS UMC CS is a fully manual wide-angle lens for Pentax K-mount cameras. Key features include:

Overview. With a focal length equivalent to 24mm after crop factor, the Rokinon 16mm is a great option for landscapes, architecture, and general wide-angle shots. It offers a wide 83.1° angle of view with a 7.87-in. minimum focusing distance, making it great for for exaggerated perspective shots.

Low-Light Shooting. The fast f/2 aperture not only enables low-light shooting, but also allows more background separation for improved depth of field.

Optics. Two aspherical elements and one extra-low dispersion element provide sharp, high-quality images with minimum chromatic aberration. The UMC coating reduces ghosting and lens flare and ensures even light transmission.

Roughing It (not really). This lens provides no electronic communication with the camera. You must manually make all aperture and focus adjustments on the lens itself. The aperture you select won’t be displayed on the camera, and it won’t show up in the EXIF data.