AUTO REVUENON 50mm F1.9 lens. This is a very rare manual lens in excellent condition. This lens is a revuenon product from the former West German company revue. The company received OEM supplies from various countries. The lens is marked JAPAN, and is likely the same model as the CINON 50mm F1.9. CINON lenses may have been made by Tomioka Optical, and this revuenon is extremely rare, making it a lens that I fell into the rabbit hole for (although there is no proof that it was made by Tomioka Optical). The mount is Pentax K-mount. As it is a K-mount, I will include genuine Pentax front and rear lens caps as accessories. I will attach a Sony E-mount adapter. I have used it with care. After use, I clean it and store it in a dehumidified storage box. It is very clean. I can see a very small amount of dust particles with the naked eye, but there is no mold or clouding. It is also very clear in actual prints. The knurling, aperture ring, and aperture blades are also smooth. Regarding a previous listing, a customer exchanged parts and returned the item due to a defect. Therefore, I will not accept any claims or returns. Thank you for your understanding. This is a recommended lens that I have cherished. Thank you very much. - Model: AUTO REVUENON 50mm f/1.9 - Country of Manufacture: JAPAN - Aperture: f/1.9 - f/16 - Focal Length: 50mm - Mount Type: M42 Screw - Minimum Focusing Distance: 0.5m Thank you for viewing.