JP 2026-57675 A — Tomohiro Kobayashi
| 15 ELEMENTS / 12 GROUPS |
| DESIGN f ≈ 87.306 mm |
| INFINITY F/2.9093 |
| ALL SPHERICAL |
Internal two-group focus: G2 (F1, element 6) and G4 (F2, cemented elements 11–12) both move toward the image from infinity to close focus, by 13.40 mm and 15.00 mm; G1, the stop with G3 (P) and G5 stay fixed. Published Example 1 spacing endpoints; close distance is the calculated d-line paraxial object-to-image conjugate, 0.224235550734 m (0.99406×). The patent prints 0.2274085 m, which does not focus on the unchanged image plane. Intermediate gap interpolation and distance labels are approximate. The infinity-calibrated physical iris remains fixed; printed close Fno 5.8166 is not reproduced.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | FDS24-W class (HOYA; coordinate-compatible) |
| L2 | Biconcave Negative | BACD5 class (HOYA; coordinate-compatible) |
| L3 | Biconvex Positive | FCD515 class (HOYA; coordinate-compatible) |
| L4 | Negative Meniscus | NBFD25 class (HOYA; coordinate-compatible) |
| L5 | Biconvex Positive | FCD515 class (HOYA; coordinate-compatible) |
| L6 | Biconcave Negative | PCD51 class (HOYA; coordinate-compatible) |
| L7 | Positive Meniscus | FCD1 class (HOYA; coordinate-compatible) |
| L8 | Biconcave Negative | FD225 class (HOYA; coordinate-compatible) |
| L9 | Positive Meniscus | S-NPH4 class (OHARA; coordinate-compatible) |
| L10 | Biconvex Positive | TAC6L class (HOYA; coordinate-compatible) |
| L11 | Positive Meniscus | FDS20-W class (HOYA; coordinate-compatible) |
| L12 | Biconcave Negative | S-LAL14 class (OHARA; coordinate-compatible) |
| L13 | Biconvex Positive | FCD100 class (HOYA; coordinate-compatible) |
| L14 | Biconcave Negative | LAC8 class (HOYA; coordinate-compatible) |
| L15 | Positive Meniscus | FC5 class (HOYA; coordinate-compatible) |