Olympus M.Zuiko Digital ED 17mm f/1.2 PRO Overview Pairing a sophisticated optical design with an exceptionally bright maximum aperture, the M.Zuiko Digital ED 17mm f/1.2 PRO from Olympus is a versatile wide-angle, 34mm-equivalent prime for Micro Four Thirds mirrorless cameras. The lens's calling card is its fast f/1.2 maximum aperture, which suits working in difficult lighting conditions and avails greater control over depth of field. Also, a complex 15 elements, 11 groups construction combines extra-low dispersion, aspherical, and high refractive index elements to significantly reduce both chromatic and spherical aberrations for notable image clarity, sharpness, and color accuracy. A nine-blade aperture is featured as well, to achieve a smooth bokeh quality when working with shallow depth of field techniques, and a Z Coating Nano has been applied to individual elements to limit flare and ghosting for improved contrast. Beyond the imaging assets, the lens' physical design is characterized by a weather-sealed construction to benefit working in harsh climates. It also features a Movie & Still Compatible (MSC) autofocus system for smooth, quiet, and fast focusing performance that is suitable to both stills and video recording. A manual focus clutch permits quick switching to MF control and a printed depth of field scale is also featured on the lens barrel for pre-focusing and hyper focal focusing techniques.