US 4,182,550 Embodiment 2 — Minolta / Yamaguchi
| 7 ELEMENTS / 6 GROUPS |
| f ≈ 50.0 mm |
| F/1.4 |
| 2ω ≈ 46° |
| ALL SPHERICAL |
Unit focus — entire 7-element optical assembly translates forward on a helicoid barrel.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | 789457 - high-index lanthanum flint (catalog unresolved) |
| L2 | Positive Meniscus | Q-LASFPH2S (Nikon) |
| L3 | Negative Meniscus | S-TIM35 class (OHARA, near match Δnd = 0.0017) |
| L4 | Biconcave Negative | S-TIH4 (OHARA) |
| L5 | Biconvex Positive | S-LAM2 (OHARA, close match Δνd = 0.21) |
| L6 | Positive Meniscus | S-LAH51 (OHARA) |
| L7 | Biconvex Positive | S-LAL10 (OHARA) |
Detailed analysis available in the interactive viewer above.