JP 2020-030383 A, Numerical Example 1 — Takeshi Asakura
| 10 ELEMENTS / 6 GROUPS |
| DESIGN f = 53.95 mm |
| DESIGN F/1.46 |
| 3 ASPHERICAL SURFACES / 2 ELEMENTS |
PUBLISHED: only G2, the single negative element L21, moves, travelling 5.52 mm toward the image between infinity and the patent's 500 mm state, which matches Sigma's 50 cm minimum focus distance. G1, the stop and G3 stay fixed. Both states are kept as printed, and their gap totals differ by 0.0001 mm from rounding. Positions between them are inferred, not Sigma's focus cam.
| Element | Type | Glass |
|---|---|---|
| L11 | Positive Meniscus | FDS18 (HOYA catalog equivalent; production supplier unspecified) |
| L12 | Biconvex Positive (Asph) | M-FCD500 (HOYA catalog equivalent; production supplier unspecified) |
| L13 | Negative Meniscus | S-NBH56 (OHARA catalog equivalent; production supplier unspecified) |
| L14 | Biconvex Positive | TAC8 (HOYA catalog equivalent; production supplier unspecified) |
| L21 | Negative Meniscus | S-BAL41 (OHARA catalog equivalent; production supplier unspecified) |
| L31 | Negative Meniscus | E-FD2 (HOYA catalog equivalent; production supplier unspecified) |
| L32 | Biconvex Positive | TAFD37 (HOYA catalog equivalent; production supplier unspecified) |
| L33 | Biconcave Negative | FF5 (HOYA catalog equivalent; production supplier unspecified) |
| L34 | Biconcave Negative | E-CF6 (HOYA catalog equivalent; production supplier unspecified) |
| L35 | Biconvex Positive (Asph) | M-TAF105 (HOYA catalog equivalent; production supplier unspecified) |