Patents were found for a Sigma 13mm f/2 APS-C and Sigma 18mm f/2 Full Frame lens. Sigma has a lot of patents for lenses that they haven’t brought to market, but these sound like they could be useful designs. Sigma 13mm F2 DC DN (APS-C) Sigma 18mm F2 DG DN (Full Frame) Example 2 (for … Continue reading Sigma 13mm F2 DC DN and Sigma 18mm F2 DG DN Patents Found