US 8,049,968 B2 — Hisayuki Yamanaka, Dayong Li
| 18 ELEMENTS / 12 GROUPS |
| PATENT 72.06-388.09mm |
| MARKETED 70-400mm f/4-5.6 |
| 2 ED ELEMENTS |
| G5 INNER FOCUS |
Inner focus by the net-positive fifth zoom group G5. At 1.5 m, G5 shifts objectward while D20 decreases and D26 increases by the same amount; back focus remains fixed.
| Element | Type | Glass |
|---|---|---|
| L11 | Negative Meniscus | TAF3 (Hoya equivalent, 804-465) |
| L12 | Biconvex Positive | FCD1 (Hoya equivalent, 497-816; ED fluorophosphate crown) |
| L13 | Biconvex Positive | FCD1 (Hoya equivalent, 497-816; ED fluorophosphate crown) |
| L21 | Negative Meniscus | PCD4 (Hoya equivalent, 618-634) |
| L22 | Biconcave Negative | FC5 (Hoya equivalent, 487-704; fluor crown) |
| L23 | Positive Meniscus | NBFD15 (Hoya equivalent, 806-333) |
| L31 | Biconvex Positive | PCD4 (Hoya equivalent, 618-634) |
| L32 | Biconcave Negative | TAFD5F (Hoya equivalent, 835-427) |
| L33 | Biconvex Positive | FDS90 (Hoya equivalent, 847-238) |
| L41 | Near-Plano Biconcave Negative | FDS90 (Hoya equivalent, 847-238) |
| L42 | Biconvex Positive | Ref.E-F8 (Hoya reference equivalent, 596-392) |
| L51 | Negative Meniscus | FDS90 (Hoya equivalent, 847-238) |
| L52 | Biconvex Positive | PCD4 (Hoya equivalent, 618-634) |
| L53 | Negative Meniscus | NBFD15 (Hoya equivalent, 806-333) |
| L54 | Biconvex Positive | FDS90 (Hoya equivalent, 847-238) |
| L61 | Negative Meniscus | PCD4 (Hoya equivalent, 618-634) |
| L62 | Positive Meniscus | E-FD13 (Hoya equivalent, 741-278) |
| L63 | Biconcave Negative | TAF3 (Hoya equivalent, 804-465) |