LEICA DG VARIO-SUMMILUX 20-50mm / F1.7 ASPH. H-X2550 lens is built for mirrorless Micro Four Thirds (MFT) mount cameras, enabling F1.7 aperture brightness throughout the entire 50-100mm (35mm camera equivalent) zoom range. Its exceptionally high optical performance is suitable for both professional photographers and videographers. Comprising 17 elements in 12 groups, the lens system features three aspherical lenses and four ED (Extra-low Dispersion) lenses that effectively suppress the axial chromatic aberration and chromatic aberration of magnification. Spherical aberration and distortion are also corrected by the aspherical lenses for stunningly high resolution. The use of aspherical lenses and the optimum design of the lens system results in a compact size and light weight. Compatibility with a maximum 240-fps high-speed sensor drive realizes high-speed, high-precision auto focusing. In addition to the silent operation achieved by the inner focus drive system, the stepless aperture ring and micro-step drive system in the aperture control section help the camera to smoothly catch up to brightness changes when zooming or panning. The optical design achieves exceptional barycentric stability to minimize image shifts during zooming. A focus ring is equipped for intuitive, precise focusing and linear/ non-linear setting can also be switched with this ring.