overview [Publication number] P2023090116 [Release date] 2023-06-29 [Title of Invention] Imaging Optical System [Application date] 2021-12-17 [Applicant] [Identification number] 000131326 [Name] Sigma Corporation Kind Code: A1 A compact image forming optical system having a small open F value over the entire zoom range is provided. 2. Description of the Related Art In recent years, a so-called … Continue reading Sigma 50-140mm F/2.8 DC DN and Sigma 70-200mm f/2.8 DG DN Patents Found