55mm · f/1.8
The Mamiya Sekor 55mm f/1.8 is a vintage all-metal lens praised for its outstanding optical quality and character. It offers excellent edge sharpness and contrast wide open, with negligible focus shift and well-controlled aberrations (reddit quoting bench tests). Weaknesses include slight curvature of field and a stiff focus ring on some copies. Build is solid, all-metal, and it suits photographers seeking an affordable, characterful standard lens for manual focus on mirrorless cameras. The non-SX version is recommended for adapter compatibility.