SIGMA 20mm F1.4 DG HSM Art for Nikon F Brand: Sigma Art (Sigma) Release Date: 2015/11/20 Lens Type: Prime/Single Focal Length Focal Range: Ultra Wide Optical Zoom: 1x Focus: Autofocus Mount: Nikon F Compatible Sensor Size (Max): Full Frame Focal Length (Wide): 20mm Focal Length (Telephoto): 20mm Maximum Aperture: f/1.4 Minimum Focusing Distance (m): 0.276m Features of Interchangeable Lens: Circular Aperture Image Stabilization: None Filter Attachment: Not Possible Dimensions (Maximum Diameter): 90.7mm Color: Black Thank you for viewing. I have been using it without any problems with AF until recently. There is some dust, but there are no issues with the image quality. I am selling it because I am replacing the lens.