Versatility within a short telephoto range, the Leica DG Vario-Summilux 25-50mm f/1.7 ASPH., from Panasonic, is a 50-100mm-equivalent zoom for Micro Four Thirds mirrorless cameras. Ideal for portraiture, fashion, events, and other mid-range subjects, this lens pairs the useful focal length range with an impressively bright constant f/1.7 maximum aperture, advanced optics, and a portable form factor.