WO 2021/039813 A1 — Masashi Yamashita, Tomoki Ito, Tomonori Kuribayashi, Keigo Koida, Satoshi Miwa, Yoko Komatsubara, Katsuya Watanabe, Azuna Nonaka, Ayumu Makida
| 10-20 mm DX zoom |
| 14 elements / 11 groups; 3 aspherical elements |
| Patent f = 10.310 / 14.992 / 19.394 mm |
| Patent FNO = 4.625 / 5.233 / 5.828 |
| G3 internal focus; L23 VR group |
Internal focus by G3 (L31-L32) moving image-side. Close-focus gaps are paraxially inferred from the official 0.22 m MFD because Example 2 publishes only infinity zoom spacings.
| Element | Type | Glass |
|---|---|---|
| L11g | Negative Meniscus | J-LASF016 / N-LAF34 class (catalog-equivalent high-index lanthanum flint) |
| L11r | Composite resin asphere | Resin / polymer layer (patent-specified) |
| L12r | Composite resin asphere | Resin / polymer layer (patent-specified) |
| L12g | Negative Meniscus | S-LAH53 (OHARA catalog equivalent; production supplier unspecified) |
| L13 | Biconcave Negative | 683548 - patent-specified glass (theta_gF=0.5501; unresolved) |
| L14 | Biconvex Positive | J-SF1 (Hikari-equivalent dense flint) |
| L21 | Biconvex Positive | J-SF10 (Hikari-equivalent dense flint) |
| L22 | Biconcave Negative | TAFD35 / TAFD35L (Hoya-equivalent high-index flint) |
| L23 | Positive Meniscus | BK7-family crown (patent nd=1.51680, νd=63.88) |
| L24 | Biconvex Positive | J-LLF6 (Hikari-equivalent light flint) |
| L25 | Negative Meniscus | TAFD35 / TAFD35L (Hoya-equivalent high-index flint) |
| L31 | Biconcave Negative | TAFD35 / TAFD35L (Hoya-equivalent high-index flint) |
| L32 | Positive Meniscus | BK7-family crown (patent nd=1.51680, νd=63.88) |
| L41 | Positive Meniscus (1× Asph) | 531559 - patent-specified crown-like glass (theta_gF=0.5684; unresolved) |
| L42 | Biconcave Negative | TAFD35 / TAFD35L (Hoya-equivalent high-index flint) |
| L43 | Biconvex Positive | J-FK5 (Hikari-equivalent low-dispersion fluor-crown) |