The Pentax SMCP-DA 17-70mm f/4 AL (IF) SDM Lens is a high-quality fixed-aperture f/4 lens designed exclusively for use with digital SLR cameras. This lens brings together advanced optical technologies, including aspherical elements, special optical-glass elements, and original lens coatings. It offers a versatile wide to medium-telephoto zoom range, and allows for a wider range of shooting applications over the more standard zoom lenses.