Sigma 24-135mm f/2.8-4.5 Aspherical IF Lens for Pentax SLR Cameras Super wide range of angles of view from 84.1 to 18.2 degrees Internal focusing system, which eliminates front lens rotation, allowing use of polarizing filters and Petal type hoods 24mm focal length this lens has a fast F2.8 maximum aperture 24-135mm Focal length Minimum focusing distance of less than 20 inches