WO 2021/246545 A1 — Jung Du Lee
| 9 elements / 8 groups |
| f = 18.541 mm patent; 18.548 mm computed |
| Fno = 2.85 design; f/2.8 marketed |
| 2ω = 100.1° |
| 3 aspherical / 3 ED / 2 HR elements |
Inner focusing by the positive G21 group (L61 + L71). D1 decreases and D2 increases by 0.932 mm from infinity to 0.25 m, with G11 and G31 fixed.
| Element | Type | Glass |
|---|---|---|
| L11 | Negative Meniscus | 923209 dense flint (E-FDS1 / N-SF66 / H-ZF62 equivalent) |
| L21 | Neg. Meniscus (2× Asph) | Unmatched crown (514/637, PGM/BK7-family) |
| L31 | Biconcave Negative | S-FPL51 / FCD1 class (ED fluorophosphate) |
| L41 | Biconvex Positive | 001291 high-index lanthanum flint (TAFD55 / S-LAH99 class) |
| L51 | Positive Meniscus | S-FPL51 / FCD1 class (ED fluorophosphate) |
| L61 | Neg. Meniscus (2× Asph) | S-LAH60 class (OHARA, close) |
| L71 | Biconvex Positive | S-FPL51 / FCD1 class (ED fluorophosphate) |
| L81 | Pos. Meniscus (2× Asph) | Unmatched lanthanum flint (770/493) |
| L91 | Biconcave Negative | H-ZF4A class (CDGM, 728283 dense flint) |