US 6,115,188 A — Akihiro Nishio, Hideki Ogawa, Makoto Misaka
| 15 ACTIVE ELEMENTS / 11 GROUPS |
| MODELED EFL ≈ 293.600 mm |
| MODELED F/2.9 |
| PATENT 2ω = 8.4° |
| INNER FOCUS / IS |
CONSTRAINED_RECONSTRUCTION: patent L2 moves imageward; close endpoint solves a rigid 14.743206096 mm L2 translation to Canon's marketed 2.5 m MFD, conserving D10 + D13 = 67.11 mm. No published close-focus spacing table exists for Example 1.
| Element | Type | Glass |
|---|---|---|
| E1 | Biconvex Positive | 497815 — UD-class low-dispersion crown (vendor unresolved) |
| E2 | Positive Meniscus | 497815 — UD-class low-dispersion crown (vendor unresolved) |
| E3 | Biconcave Negative | 786442 — high-index lanthanum glass class (vendor unresolved) |
| E4 | Biconvex Positive | Fluorite (CaF2 coefficient proxy; Canon product correlation) |
| E5 | Negative Meniscus | 487702 — high-Abbe crown class (vendor unresolved) |
| E6 | Biconvex Positive | 805254 — dense-flint class (vendor unresolved) |
| E7 | Biconcave Negative | 835427 — high-index lanthanum class (vendor unresolved) |
| E8 | Negative Meniscus | 847239 — high-index flint class (vendor unresolved) |
| E9 | Biconvex Positive | 720502 — lanthanum crown class (vendor unresolved) |
| E10 | Biconvex Positive | 847239 — high-index flint class (vendor unresolved) |
| E11 | Biconcave Negative | 603606 — crown class (vendor unresolved) |
| E12 | Biconcave Negative | 772496 — high-index lanthanum glass class (vendor unresolved) |
| E13 | Biconvex Positive | 720502 — lanthanum crown class (vendor unresolved) |
| E14 | Negative Meniscus | 834372 — high-index lanthanum flint class (vendor unresolved) |
| E15 | Plano-Convex Positive | 697555 — lanthanum crown class (vendor unresolved) |