US 3,615,125 — Takashi Higuchi, Soichi Nakamura
| 15 elements / 10 groups |
| computed f = 80.009–200.341 mm |
| constant f/4.5 |
| all spherical |
| focus not internally reconstructed |
NO_INTERNAL_RECONSTRUCTION: the patent publishes infinity-focus zoom kinematics only. The production 1.8 m minimum focus distance is catalog metadata; all authored variable-gap pairs remain identical at infinity and close focus, so no close-focus optical motion is modeled.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | 620603 - SK16 class (vendor unresolved) |
| L2 | Biconvex Positive | BACD6 (HOYA catalog-equivalent; patent supplier unspecified) |
| L3 | Biconcave Negative | 755275 - SF4 class (vendor unresolved) |
| L4 | Biconvex Positive | 689311 - SF8 class (vendor unresolved) |
| L5 | Biconcave Negative | S-APL1 (OHARA; 517696) |
| L6 | Biconcave Negative | 620603 - SK16 class (vendor unresolved) |
| L7 | Biconvex Positive | 620603 - SK16 class (vendor unresolved) |
| L8 | Negative Meniscus | 620363 - F2 class (vendor unresolved) |
| L9 | Biconvex Positive | 548459 - LLF1 class (vendor unresolved) |
| L10 | Biconvex Positive | 532489 - LLF6 class (vendor unresolved) |
| L11 | Biconcave Negative | 785261 - SFS3 / dense short-flint class (vendor unresolved) |
| L12 | Biconvex Positive | 517642 - BK7 class (vendor unresolved) |
| L13 | Biconcave Negative | 744449 - LAF2 class (vendor unresolved) |
| L14 | Plano-Convex Positive | SF15 (Sumita coefficient-backed equivalent), 699300 |
| L15 | Biconvex Positive | BASF7 (Sumita coefficient-backed equivalent), 702411 |