DE 2157160 A1 Example 1 — Olympus / Nakagawa
| Patent Example 1: 10 elements / 6 groups |
| Production correlation: 8mm f/2.8 OM circular fisheye |
| 180° field, 23 mm circular image |
| All-spherical prescription |
Unit-focus approximation. The patent publishes only the infinity prescription; runtime focus varies the final back-focus gap after surface 16.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | S-BAL35 class (OHARA; SK5 / 589/610 equivalent) |
| L2 | Positive Meniscus | S-TIH11 class (OHARA; SF11 / 785/256 equivalent) |
| L3 | Negative Meniscus | S-BAL35 class (OHARA; SK5 / 589/610 equivalent) |
| L4 | Negative Meniscus | J-LAK02 class (Hikari; 670/573) |
| L5 | Positive Meniscus | H-ZF39 class (CDGM; 667/330) |
| L6 | Negative Meniscus | 787501 — vintage high-index lanthanum flint (probable; no exact public catalog match) |
| L7 | Biconvex Positive | 603423 — BaSF5-class barium dense flint (no exact public catalog match) |
| L8 | Positive Meniscus | J-PKH1 class (Hikari; 517/693 low-dispersion crown) |
| L9 | Negative Meniscus | N-SF66 class (SCHOTT; 923/209 very dense flint) |
| L10 | Biconvex Positive | J-PKH1 class (Hikari; 517/693 low-dispersion crown) |
Detailed analysis available in the interactive viewer above.