A staple of wide-angle versatility, the Lumix S PRO 16-35mm f/4 from Panasonic is an L-mount wide zoom featuring an f/4 constant maximum aperture. An optimized optical design incorporates a series of aspherical, low dispersion, and high refractive index elements, to control a variety of aberrations, color fringing, and distortion for sharp, clear, well-corrected imagery throughout the zoom range. Complementing the optics is a unique double-magnet linear motor focus system, which provides high-speed response and power while remaining compact in size. The lens also sports a rounded nine-blade diaphragm, which contributes to the quality of bokeh, and a weather-sealed construction to suit working in a variety of weather conditions.