US 6,437,923 B1 — Yasuharu Yamada
| 28-200mm marketing / 29.07-193.0mm patent design |
| 15 PHYSICAL LENS PIECES / 14 GROUPS |
| 3 COMPOSITE ASPHERICAL LENSES |
| 0.49m MFD / 1:4 AT 200mm (MARKETING) |
CONSTRAINED_RECONSTRUCTION: patent-published G2-only inner focus, solved at the Tamron A03 0.49 m MFD with a fixed paraxial image plane; G1/G3/G4 remain fixed, only G2 translates, and D6 + D15 is conserved at every zoom station.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | 847238 (vendor-neutral d-line class) |
| L2 | Biconvex Positive | 697555 (vendor-neutral d-line class) |
| L3 | Positive Meniscus | 773496 (vendor-neutral d-line class) |
| L4r | Negative Meniscus (Asph) | Unmatched (composite-asphere resin; nd=1.53610, νd=41.2) |
| L4 | Negative Meniscus | 835427 (vendor-neutral d-line class) |
| L5 | Biconcave Negative | 720502 (vendor-neutral d-line class) |
| L6 | Biconvex Positive | 847238 (vendor-neutral d-line class) |
| L7 | Negative Meniscus | 835427 (vendor-neutral d-line class) |
| L8r | Meniscus Resin Layer (Asph) | Unmatched (composite-asphere resin; nd=1.53610, νd=41.2) |
| L8 | Biconvex Positive | 800422 (vendor-neutral d-line class) |
| L9 | Positive Meniscus | 720502 (vendor-neutral d-line class) |
| L10 | Biconcave Negative | 847238 (vendor-neutral d-line class) |
| L11 | Biconvex Positive | 516641 (vendor-neutral d-line class) |
| L12 | Negative Meniscus | 806409 (vendor-neutral d-line class) |
| L13 | Biconvex Positive | 518590 (vendor-neutral d-line class) |
| L13r | Meniscus Resin Layer (Asph) | Unmatched (composite-asphere resin; nd=1.53610, νd=41.2) |
| L14 | Biconvex Positive | 532489 (vendor-neutral d-line class; source-corrected nd) |
| L15 | Biconcave Negative | 773496 (vendor-neutral d-line class) |