Lens Lab
    Pentax smc DA 17-70mm F4.0 AL (IF) SDM
    Pentax smc DA 17-70mm F4.0 AL (IF) SDM

    Pentax smc DA 17-70mm F4.0 AL (IF) SDM

    17–70mm · f/4

    Overview

    The Pentax smc DA 17-70mm f/4 AL (IF) SDM is a constant-aperture standard zoom for APS-C Pentax DSLRs, offering a useful 26-107mm equivalent range. Optically, it delivers very sharp results, especially at 50mm and f/8, with good center sharpness wide open. Weaknesses include higher chromatic aberration at wide angles and challenging manual focusing due to a short throw. Build quality is high with quality materials and smooth controls, though the SDM autofocus is silent but not the fastest. It suits Pentax users seeking a versatile, well-built walkaround lens with constant aperture.