The M.Zuiko Digital ED 40-150mm f/2.8 PRO from Olympus is a versatile 80-300mm equivalent telephoto zoom for Micro Four Thirds mirrorless cameras. As part of the PRO series of advanced lenses, this zoom distinguishes itself with a bright f/2.8 constant maximum aperture for consistent illumination throughout the zoom range to suit working in a variety of lighting conditions. A manual focus clutch permits quick switching between AF and MF, and programmable L-Fn button avail lens-based control over shooting settings.