US 4,210,388 EXAMPLE 1 — OLYMPUS / Y. IKEDA
| 11 ELEMENTS / 9 GROUPS |
| f ≈ 21 mm (marketed) / 28.5 mm (computed) |
| F/2.0 |
| 2ω = 92° |
| ALL SPHERICAL |
Unit focus (BFD only). Production lens uses floating elements — not modeled here.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | 639449 — LAC14 / BaLF5-class barium lanthanum flint (no exact public catalog match) |
| L2 | Negative Meniscus | S-LAL59 (OHARA, 734515) / LaK9 class |
| L3 | Negative Meniscus | S-LAH66 (OHARA) |
| L4a | Plano-Convex | F2 / TIF1 (Schott / OHARA) |
| L4b | Plano-Convex | F2 / TIF1 (Schott / OHARA) |
| L5 | Negative Meniscus | S-LAL14 (OHARA, 697555) / LaK8 class |
| L6 | Biconvex Positive | 593348 — LF7-class light flint (no exact public catalog match) |
| L7 | Positive Meniscus | S-LAM52 (OHARA, 720437) / LaF3 class |
| L8 | Biconcave Negative | S-NPH53 (OHARA, 847239) / SF57 class |
| L9 | Biconvex Positive | 713539 — LaK21 / LAC11-class lanthanum crown (no exact public catalog match) |
| L10 | Negative Meniscus | S-LAL10 (OHARA, 720502) / LaK14 class |
Detailed analysis available in the interactive viewer above.