Type SK Prime lenses are based upon vintage 1960s Canon rangefinder lenses. 3 wide focal lengths have been created by adding custom built optics to the existing glass . They have medium contrast and pleasing golden flares These lenses are characterized by a ton of wide open center sharpness and resolution as well as low chromatic aberration. The bokeh and focus fall off gives them true vintage texture . The new housings for these lenses feature 110mm fronts, 330 degree focus rotation, PL mounts, and matching gear positions.