- Specifications
- Block diagram
| Marketed | December 1956 |
| Original Price | 32,500 yen (w/case) |
| Lens Construction (group) | 5 |
| Lens Construction (element) | 5 |
| No. of Diaphragm Blades | 6 |
| Minimum Aperture | 22 |
| Closest Focusing Distance (m) | 1 |
| Maximum Magnification (x) | — |
| Filter Diameter (mm) | 40 |
| Maximum Diameter x Length (mm) | 48 x 15 |
| Weight (g) | 145 |
A super wide angle lens with a diagonal angle of view 82°, developed based on Topogon (manufactured by Carl Zeiss, Germany. Angle of view: 100°. f/6.3). This lens has a unique optical system: a spherical lens element with a very high refraction index is used as the first lens element and a special optical glass lens element with the infinite radius of curvature is used as the rearmost lens element. This lens was the fastest lens in the world as a 25mm lens at the time.
