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. The HOYA PRO 1D Protector is the ultimate in clear filters. It will not affect the color balance or performance of your lenses in the slightest. However, constant use will protect your valued lenses from expensive front element damage which could be caused by dirt, knocks or scratches.