SIGMA 24mm F1.8 EX DG ASPHERICAL MACRO (Pentax Mount) Features: The large aperture wide-angle lens for close up photography. This large-aperture wide-angle lens is equipped macro focusing capability with a maximum magnification of 1:2.7 and fast F1.8 maximum aperture. The use of aspherical lenses are offered for superior peripheral brightness and compensation of aberrations and astigmatism. This is an ideal DG lens for Digital SLR cameras. Macro capability This lens is capable of Macro photography at minimum focusing down to 18cm (7.1 inch) (reproduction ratio 1:2.7). It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. Also this allows the use of a "Petal-type Hood" , which is superior light blocking effect. Aspherical lens It incorporates a floating focus system and uses two aspherical lens elements for minimizing distortion, spherical aberration and astigmatism. Specs: Lens C