JP H01-189622 A — Sadatoshi Takahashi
| 10 ELEMENTS / 9 GROUPS |
| DESIGN EFL 29.083-67.894 mm |
| DESIGN f/3.6-4.6 |
| 1 ASPHERICAL SURFACE |
| FRONT-GROUP FOCUS |
Front-group focus (G1). The patent publishes infinity zoom spacings only; close-focus D6 values are a constrained paraxial reconstruction solved at the official rounded 0.39 m MFD, with the image-plane reference assumed. The reconstruction is not a published production cam law.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus (convex to object) | 834372 — dense lanthanum flint (catalog vendor unresolved) |
| L2 | Biconcave Negative (1× Asph) | 583594 — barium/dense crown (catalog vendor unresolved) |
| L3 | Positive Meniscus (convex to object) | 805254 — dense flint (catalog vendor unresolved) |
| L4 | Biconvex Positive | 652585 — lanthanum crown (catalog vendor unresolved) |
| L5 | Positive Meniscus (convex to object) | 487702 — low-index fluor/light crown (catalog vendor unresolved) |
| L6 | Positive Meniscus (convex to object) | 487702 — low-index fluor/light crown (catalog vendor unresolved) |
| L7 | Biconcave Negative | 847239 — very dense high-dispersion flint (catalog vendor unresolved) |
| L8 | Biconvex Positive | 755275 — dense flint (catalog vendor unresolved) |
| L9 | Negative Meniscus (convex to image) | 834372 — dense lanthanum flint (catalog vendor unresolved) |
| L10 | Positive Meniscus (convex to image) | 603607 — dense crown (catalog vendor unresolved) |