US 2004/0223070 A1 — Takashi Shirasuna
| 10 ELEMENTS / 9 GROUPS |
| PATENT 28.91-101.32mm |
| MARKETED 28-105mm f/4-5.6 |
| 1 ASPHERICAL SURFACE |
| L2 INNER FOCUS |
Inner focus by rigid translation of negative unit L2. In the cover-plate-folded renderer model at Canon's 0.48 m MFD, L2 moves objectward by 2.328 mm at wide, 3.115 mm at 50.07 mm, and 6.421 mm at tele; D3 decreases while D9 increases by the same amount.
| Element | Type | Glass |
|---|---|---|
| L11 | Biconvex Positive | S-LAL14 (OHARA catalog equivalent; vendor inferred, 697-555) |
| L12 | Biconcave Negative | PBH53 / PBH53W (OHARA historical equivalent; vendor inferred, 847-239) |
| L21 | Negative Meniscus | S-LAM60 (OHARA catalog equivalent; vendor inferred, 743-493) |
| L22 | Biconcave Negative | S-LAL8 (OHARA catalog equivalent; vendor inferred, 713-539) |
| L23 | Positive Meniscus | PBH53 / PBH53W (OHARA historical equivalent; vendor inferred, 847-239) |
| L31 | Biconvex Positive | S-LAL14 (OHARA catalog equivalent; vendor inferred, 697-555) |
| L32 | Negative Meniscus | PBH53 / PBH53W (OHARA historical equivalent; vendor inferred, 847-239) |
| L41 | Biconvex Positive | S-FSL5 (OHARA catalog equivalent; vendor inferred, 487-702) |
| L42 | Negative Meniscus (rear asphere) | Unmatched (polycarbonate-class optical resin inferred from nd=1.583060, νd=30.2) |