JP 2021-92636 A, Numerical Example 1 — Hiromichi Ochiai
| 22 ELEMENTS / 16 GROUPS |
| DESIGN f = 103.00–387.40 mm |
| DESIGN F/5.15–6.50 |
| ALL SPHERICAL |
| 1 FLD / 4 SLD ELEMENTS |
Inner focus. The patent prints infinity spacings only and focuses by moving the single positive element L18 (G6) toward the object (¶0057). Here G6 moves that way, D30 shorter and D32 longer by the same amount, with the image plane fixed; the travel to Sigma's minimum focus distance is 2.90 mm at 103 mm (1.12 m), 7.08 mm at 200.08 mm (1.36 m, assumed) and 18.42 mm at 387.4 mm (1.60 m). These finite spacings are derived, not printed. The zoom positions between the three printed focal lengths follow a derived cam with G2 and G8 fixed, not Sigma's factory cam.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | TAF3D (HOYA catalog equivalent; production supplier unspecified) |
| L2 | Biconvex Positive | FCD1 (HOYA catalog equivalent; production supplier unspecified) |
| L3 | Biconvex Positive | FCD100 (HOYA catalog equivalent; production supplier unspecified) |
| L4 | Positive Meniscus | S-NBH8 (OHARA catalog equivalent; production supplier unspecified) |
| L5 | Biconvex Positive | E-FL6 (HOYA catalog equivalent; production supplier unspecified) |
| L6 | Biconcave Negative | TAFD35 (HOYA catalog equivalent; production supplier unspecified) |
| L7 | Negative Meniscus | TAF1 (HOYA catalog equivalent; production supplier unspecified) |
| L8 | Biconcave Negative | TAC8 (HOYA catalog equivalent; production supplier unspecified) |
| L9 | Biconvex Positive | FDS90 (HOYA catalog equivalent; production supplier unspecified) |
| L10 | Biconvex Positive | LAC14 (HOYA catalog equivalent; production supplier unspecified) |
| L11 | Biconvex Positive | E-FL5 (HOYA catalog equivalent; production supplier unspecified) |
| L12 | Negative Meniscus | TAFD65 (HOYA catalog equivalent; production supplier unspecified) |
| L13 | Positive Meniscus | E-FD15 (HOYA catalog equivalent; production supplier unspecified) |
| L14 | Negative Meniscus | TAFD37A (HOYA catalog equivalent; production supplier unspecified) |
| L15 | Positive Meniscus | FCD600 (HOYA catalog equivalent; production supplier unspecified) |
| L16 | Negative Meniscus | TAFD55 (HOYA catalog equivalent; production supplier unspecified) |
| L17 | Biconvex Positive | FCD515 (HOYA catalog equivalent; production supplier unspecified) |
| L18 | Biconvex Positive | PCD51 (HOYA catalog equivalent; production supplier unspecified) |
| L19 | Negative Meniscus | TAFD55 (HOYA catalog equivalent; production supplier unspecified) |
| L20 | Biconcave Negative | FCD705 (HOYA catalog equivalent; production supplier unspecified) |
| L21 | Biconvex Positive | S-NBH58 (OHARA catalog equivalent; production supplier unspecified) |
| L22 | Negative Meniscus | TAFD65 (HOYA catalog equivalent; production supplier unspecified) |