The Leica DG Vario-Summilux 10-25mm f/1.7 ASPH. from Panasonic 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. Wide-to-normal zoom is designed for Micro Four Thirds mirrorless cameras and offers a 20-50mm equivalent focal length range. Three aspherical elements, four extra-low dispersion elements, and one ultra-high-refractive index element all combine to suppress color fringing, chromatic aberrations, and spherical aberrations for high clarity, sharpness, and color accuracy. The physical aperture ring has a stepless, de-clicked design for smooth, silent aperture switching to benefit video applications.