JP 2009-282554 A — Makoto Misaka
| 10 elements / 8 air-spaced groups |
| 28-90mm f/4-5.6 |
| Canon EF / 135 format |
| 4 moving zoom groups (- / + / - / +) |
| 1 aspherical surface |
| Micro-USM; front-group focus |
CONSTRAINED_RECONSTRUCTION: the patent identifies Group 1 focusing but gives no finite-focus table. D6 close-focus values are independently solved for a 0.38 m image-plane-referenced object distance while Groups 2-4 and the image plane remain fixed; the result is not patent-published.
| Element | Type | Glass |
|---|---|---|
| E1 | Negative Meniscus, convex to object | S-BSM15 (OHARA) |
| E2 | Biconcave Negative | S-BSM15 (OHARA) |
| E3 | Positive Meniscus, convex to object | S-TIH53 (OHARA) |
| E4 | Biconvex Positive | S-BAH27 (OHARA) |
| E5 | Negative Meniscus | S-TIH53 (OHARA) |
| E6 | Biconvex Positive | S-BSM14 (OHARA) |
| E7 | Biconcave Negative | S-TIM28 (OHARA) |
| E8 | Positive Meniscus | S-TIH53 (OHARA) |
| E9 | Negative Meniscus, concave to object (1× Asph) | Unmatched (proprietary optical polymer; patent plastic-asphere class) |
| E10 | Positive Meniscus, concave to object | S-BSL7 (OHARA) |