The Panasonic Leica DG Vario-Summilux 10-25mm f/1.7 ASPH. lens is a 20-50mm-equivalent zoom for Micro Four Thirds mirrorless cameras. The impressively fast f/1.7 constant maximum aperture enables improved depth of field control and low-light shooting capabilities throughout the zoom range. Balancing the impressive f/1.7 performance, the optical design incorporates a series of low dispersion, aspherical, and high refractive index elements, which help to greatly reduce chromatic and spherical aberrations for improved clarity and sharpness. Complementing the optics, this lens is also characterized by its durable, weather-sealed physical design, along with a fast autofocus system, versatile focusing clutch design, and a stepless, de-clicked aperture ring to suit video applications.