Rokinon HD HD8M-P 8mm f/3.5 HD Fisheye Lens with Removable Hood for Pentax Manual focus; aperture range of f/3.5-22 10 elements in 7 groups 1 spherical lens minimum focusing distance of 1-foot Ultra-wide 167 diagonal field-of-view for APS-C size image formats will produce a rounded image that doesn't cover the entire frame when used with compatible full frame digital cameras or 35mm film cameras Features improved HD optics for sharper images