A unique prototype APO-Elmarit-R 100 mm, which later evolved into the series-production APO-Macro-Elmarit-R 100 mm. While the lens already closely resembles the final production version, it exhibits several distinctive prototype features and differences, including the shape of the focusing ring and the dimensions of the built-in lens hood.The lens is preserved in excellent condition. An important and highly rare Leica prototype, offering a rare insight into the development process of one of Leica’s finest macro lenses. SN: 5175934