overview [Publication number] P2024035865 [Release date] 2024-03-15 [Name of the invention] Large aperture ratio optical system [Application date] 2022-09-05 [Applicant] [Identification number] 000131326 [Name] Sigma Co., Ltd. [Problem] To realize a large aperture ratio optical system that uses an inner focus method while reducing the weight of a focus lens. [Background Art] [0002] In recent … Continue reading Sigma 20mm f/1.4 and 23mm f/1.4 Patents Found