SIGMA's lens for Sony E-mount: "20mm F1.4 DG DN | Art". It has been stored in a dehumidified storage and shows no signs of dust, debris, or scratches on the lens. This is a very bright lens with a focal length of 20mm and an F-value of 1.4, released by SIGMA and touted as the "ultimate astrophotography lens." I mainly used it for nightscape and starry sky photography, but the sharp image quality characteristic of the Art lens allows for beautiful photos even outside of nighttime shooting. I believe it is in the category of a beautiful item, but it is a used item under personal management, so I would appreciate it if those who understand this would purchase it. Specifications (quoted from the HP below) Lens construction: 15 groups, 17 elements (2 SLD lenses, 3 aspherical lenses) Angle of view: 94.5° Number of diaphragm blades: 11 (circular aperture) Minimum aperture: F16 Minimum focusing distance: 23cm Maximum magnification: 1:6.1 Filter size: φ82mm Maximum diameter x length: φ87.8mm × 113.2mm Weight: 630g Edition number: A022