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. 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 and Still Compatible (MSC) autofocus system for smooth, quiet, and fast focusing performance that is suitable for 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 intricate optical design employs one Super Extra-Low Dispersion element, three extra-low dispersion elements, one Extra-Low Dispersion Dual-Sided Aspherical element, one Extra-Low Dispersion Aspherical element, one Super High Refractive Index element, and one aspherical element, which all work in concert to control chromatic and spherical aberrations for improved clarity, reduced color fringing, and enhanced sharpness. An MSC autofocus system, along with an internal focusing design, provides quick, quiet, and precise focusing performance to benefit both still photo shooting and movie recording. Additionally, an MF clutch is used for fast changing to manual focus for more precise control. Weather-sealed construction guards the lens against dust, moisture, and freezing temperatures for working in harsh environments.