JP 2019-117419 A — Numerical Example 1
| 15 elements / 11 groups |
| Patent f = 20.69 mm |
| Patent F1.46; marketed F1.4 |
| 2 FLD + 5 SLD + 2 aspherical elements |
| Dual-group floating internal focus |
Dual-group floating internal focus: L1 fixed; L2 and stop/L3 move objectward by different amounts. Close-focus values extrapolate the patent's L2:L3 motion ratio to Sigma's published 0.276 m / 1:7.1 limit.
| Element | Type | Glass |
|---|---|---|
| E1 | Negative Meniscus | E-FDS1 (Hoya) |
| E2 | Neg. Meniscus (2x Asph) | M-LAC130 (HOYA) |
| E3 | Negative Meniscus | FCD1 (Hoya) / S-FPL51 class |
| E4 | Biconvex Positive | TAFD30 (Hoya) |
| E5 | Biconcave Negative | FCD100 (Hoya) / S-FPL53 class |
| E6 | Biconvex Positive | TAFD55 (Hoya) |
| E7 | Biconvex Positive | FCD515 (Hoya) |
| E8 | Biconvex Positive | FCD515 (Hoya) |
| E9 | Biconcave Negative | NBFD15 (Hoya) |
| E10 | Positive Meniscus | FCD100 (Hoya) / S-FPL53 class |
| E11 | Biconcave Negative | NBFD15 (Hoya) |
| E12 | Biconvex Positive | FCD515 (Hoya) |
| E13 | Biconvex Positive | FCD515 (Hoya) |
| E14 | Biconcave Negative | BAFD7 (HOYA) |
| E15 | Biconvex Positive (2x Asph) | Unmatched 764491 - moldable lanthanum-crown class (patent nd=1.76450, vd=49.10; not catalog L-LAM69) |
Detailed analysis available in the interactive viewer above.