The M.ZUIKO DIGITAL ED 12-40mm 1:2.8 PRO lens is engineered to meet the needs of professional photographers in all respects. When combined with the OLYMPUS OM-D, this large-aperture lens achieves the reputation of an unbelievably fast AF high-performance standard zoom. Its constant, bright aperture value of f2.8 at all focal lengths (equivalent to 24-80mm on a 35mm camera), combined with other sophisticated technologies including an MSC and Manual Focus Clutch mechanism, deliver high-grade image creation for a wide range of photographic styles, regardless of lighting conditions and distance. The compact and lightweight design also has a dustproof and splashproof construction compliant with professional use, expanding shooting capabilities even in the most testing of environments.