US 2013/0335830 A1 — Yoshihisa Tashiro, Yasuaki Hagiwara
| 13 ELEMENTS / 11 GROUPS |
| 18.58-53.36 mm DESIGN |
| f/3.60-5.69 MODELED |
| 4 ASPHERICAL SURFACES / 3 ASPHERICAL ELEMENTS |
| INNER FOCUS / OPTICAL IS |
| 0.25 m MFD / 0.25× MAX MAG (MARKETING) |
CONSTRAINED_RECONSTRUCTION: the patent states that only L4 moves objectward for finite focus but publishes no finite-distance spacing rows. Close-focus d11/d13 pairs are code-solved from Canon's 0.25 m MFD while conserving d11+d13. Because patent optical block G is omitted and replaced by an air-equivalent rear spacing, the same physical object position is 0.249417722857 m from the normalized image plane; the tele state gives |m| ≈ 0.246777 versus the marketed 0.25× maximum magnification.
| Element | Type | Glass |
|---|---|---|
| L1a | Negative Meniscus | 847239 — vendor unresolved |
| L1b | Positive Meniscus | 697555 — vendor unresolved |
| L2a | Negative Meniscus | 835427 — vendor unresolved |
| L2b | Biconcave Negative (1× Asph) | 851401 — vendor unresolved |
| L2c | Positive Meniscus | 923189 — vendor unresolved |
| L3 | Positive Meniscus | 773496 — vendor unresolved |
| L4 | Negative Meniscus | 883408 — vendor unresolved |
| LRa1 | Biconvex Positive | 697555 — vendor unresolved |
| LRa2 | Negative Meniscus | 847239 — vendor unresolved |
| LRa3 | Positive Meniscus (2× Asph) | 583594 — vendor unresolved |
| LRb | Biconcave Negative | 904313 — vendor unresolved |
| LRc1 | Weak Positive Meniscus (1× Asph) | Unmatched (nd=1.52996, nu_d=55.8; code 530558) |
| LRc2 | Positive Meniscus | 847239 — vendor unresolved |