WO 2026/172598 A1 — Akino Takahashi
| 18 ELEMENTS / 16 GROUPS |
| f = 71.4–196.0 mm |
| F/2.89–2.91 |
| 2ω = 34.7°–12.5° |
| 4 ASPHERICAL SURFACES |
Two-group floating internal focus (patent ¶0140): G5 moves toward the image and G6 toward the object; G1–G4, G7 and the image plane stay fixed. Close-focus spacings are a constrained reconstruction, not patent data: solved for Nikon's 0.38 / 0.6 / 0.8 m minimum focus distances, with 0.30× at wide and 0.25× at tele. The 135 mm state uses a declared travel-ratio rule (β ≈ 0.25×), and intermediate states are interpolated.
| Element | Type | Glass |
|---|---|---|
| L11 | Positive Meniscus | J-FK5 (HIKARI) — 487703 class; supplier unconfirmed |
| L12 | Negative Meniscus | NBFD29 (HOYA) — 770297 class; supplier unconfirmed |
| L13 | Plano-Convex | CaF2 (fluorite crystal) — inferred from nd, θgF and Nikon's one-fluorite construction |
| L21 | Negative Meniscus | J-KZFH4 (HIKARI) — 553551 class; supplier unconfirmed |
| L31 | Biconcave Negative | J-PKH1 (HIKARI) — 519699 class; supplier unconfirmed |
| L32 | Positive Meniscus | TAFD40 (HOYA) — 2.00069/25.46 coordinate also listed as CDGM H-ZLaF90A and HIKARI J-LASFH17; supplier unresolved |
| L33 | Biconcave Negative | FCD100 (HOYA) — 437951 class; supplier unconfirmed |
| L41 | Positive Meniscus | J-SFH8 (HIKARI) — 622307 class; supplier unconfirmed (dPgF carries the patent θgF) |
| L42 | Biconvex Positive (2× Asph) | M-FCD1 (HOYA) — 497816 class, moldable ED; supplier unconfirmed |
| L43 | Negative Meniscus | NBFD25 (HOYA) — 855252 class; supplier unconfirmed |
| L44 | Positive Meniscus | J-FKH1 (HIKARI) — 498826 class; supplier unconfirmed |
| L45 | Biconvex Positive (1× Asph) | J-PSKH4 (HIKARI) — 593670 class; not coordinate-identical (Δnd +0.00043), supplier/melt unresolved |
| L46 | Negative Meniscus | J-SFH1 (HIKARI) — 808227 class; supplier unconfirmed |
| L47 | Positive Meniscus | NBFD15 (HOYA) — 806333 class, also CDGM H-ZLaF56B; supplier unresolved |
| L51 | Biconvex Positive | J-SFH1 (HIKARI) — 808227 class; supplier unconfirmed |
| L52 | Biconcave Negative | J-LASF014 (HIKARI) — 788474 class; supplier unconfirmed |
| L61 | Biconvex Positive | J-KZFH6 (HIKARI) — 684376 class; supplier unconfirmed |
| L71 | Neg. Meniscus (1× Asph) | 583595 class — CDGM D-ZK2A / HOYA M-BACD12 coordinate family; not coordinate-identical, supplier unresolved |