US 3,743,387 — Jihei Nakagawa / Olympus Optical Co.
| 7 ELEMENTS / 6 GROUPS |
| f ≈ 55.0 mm |
| F/1.2 |
| 2ω = 43° |
| ALL SPHERICAL |
Unit focus — entire optical assembly moves forward on straight helicoid.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | LaSF (S-LAH65 family, OHARA) |
| L2 | Positive Meniscus | LaSF (S-LAH53 equivalent, OHARA) |
| L3 | Negative Meniscus | NbF/SF (dense flint family) |
| L4 | Negative Meniscus | SF (S-TIH10 equivalent, OHARA / SF10 SCHOTT) |
| L5 | Positive Meniscus | LaK (lanthanum crown family) |
| L6 | Positive Meniscus | LaK (N-LAK8 family, SCHOTT / LAC8 HOYA) |
| L7 | Biconvex Positive | LaK (N-LAK8 family, SCHOTT / LAC8 HOYA) |
Detailed analysis available in the interactive viewer above.