R50mm f/1.8 (I)
| Marketed | May 1959 |
| Original Price | 18,500 yen |
| Lens Construction (group) | 4 |
| Lens Construction (element) | 6 |
| No. of Diaphragm Blades | -- |
| Minimum Aperture | 16 |
| Closest Focusing Distance (m) | 0.6 |
| Maximum Magnifcation (x) | -- |
| Filter Diameter (mm) | 58 |
| Maximum Diameter x Length (mm) | 64.5 x 47.5 |
| Weight (g) | 295 |
