JP 2008-020656 A — Yutaka Kamimura, Ai Hoshina
| 10 ELEMENTS / 9 GROUPS |
| DESIGN f = 68.91 mm |
| DESIGN F/2.88 |
| ALL SPHERICAL |
PUBLISHED three-state floating extension: D16/BF follow JP 2008-020656 A Example 1 (infinity, 0.50x, 1.02x). Both groups extend toward the object relative to the fixed image: the first group (G1 + G2, S1-S16) by 25.19 mm then 51.23 mm, the second group (S17-S20) by 9.89 mm then 21.73 mm, so D16 opens from 1.5 to 31.0 mm. Intermediate slider positions are modeled interpolation, not published cam positions. The fixed physical iris is inferred by exact axial tracing at the nominal infinity entrance pupil for F/2.8823; reproduction of finite-focus published F/3.8824 and F/5.0151 remains unverified.
| Element | Type | Glass |
|---|---|---|
| E1 | Negative Meniscus | E-FEL2 (HOYA, coordinate equivalent) |
| E2 | Biconvex Positive | TAF1 (HOYA, coordinate equivalent) |
| E3 | Positive Meniscus | LAC14 (HOYA, coordinate equivalent) |
| E4 | Negative Meniscus | E-F5 (HOYA, coordinate equivalent) |
| E5 | Biconcave Negative | E-FL5 (HOYA, coordinate equivalent) |
| E6 | Biconvex Positive | Unmatched (anomalous-dispersion crown; catalog identity unresolved) |
| E7 | Biconvex Positive | Unmatched (anomalous-dispersion crown; catalog identity unresolved) |
| E8 | Biconvex Positive | FCD1 (HOYA, coordinate equivalent) |
| E9 | Plano-Concave | LACL60 (HOYA, coordinate equivalent) |
| E10 | Biconvex Positive | TAFD5G (HOYA, coordinate equivalent) |