There're both AF and MF versions of this lens. The one I got is MF only. The focal length sits right in the middle of my 19mm and 30mm. It can focus down to 18cm, with max magnification of 1:4, 52mm filter thread. See also Sigma 24mm F2.8 Super Wide II Lens Reviews - Sigma Lenses - Pentax Lens Review Database Some pictures on the trail at Pacifica, California.