The Olympus M. Zuiko Digital ED 12-40mm f/2.8 PRO Lens is a wide-angle to portrait-length zoom lens that is compatible with the Micro Four Thirds system. The 12-40mm focal length provides a 35mm-equivalent field of view of 24-80mm and a constant f/2.8 maximum aperture enables consistent low-light performance and shallow depth of field control throughout the zoom range. The lens construction integrates an array of aspherical, extra-low dispersion, high-refractive index, and HD lens elements to provide a comprehensive reduction in chromatic aberrations and distortion while also contributing to high overall image sharpness, clarity, and color fidelity. A high-speed imager AF linear motor drive system provides fast, smooth, and quiet focusing performance and the MSC (Movie and Still Image Compatible) designation indicates this lens' suitability for use with fast-moving subjects and video applications. Additionally, a manual focus clutch enables quick, seamless shifting between auto and manual focus control. Additionally, the lens features a dust-, freeze-, and drip-proof construction that is tailored to its use in inclement conditions.