With impressive reach and versatility, the M.Zuiko Digital ED 150-400mm f4.5 TC1.25X IS PRO, from OM System, is a super-telephoto zoom lens characterized by its expansive range, built-in teleconverter, and relatively sleek design for handheld use. Built for Micro Four Thirds cameras, this zoom offers a 300-800mm equivalent focal length range, which can be extended even further using the integrated 1.25x teleconverter for an effective 1000mm equivalent focal length. The constant f/4.5 maximum aperture affords consistent illumination throughout the zoom range and is reduced slightly to f/5.6 when the teleconverter is in use.