US 7,280,284 B2, Example 3 — Atsujiro Ishii
| 18 ELEMENTS / 12 GROUPS |
| DESIGN f = 7.1–13.7 mm |
| DESIGN F/4 |
| 4 ASPHERICAL SURFACES / 2 ELEMENTS |
PUBLISHED: the patent prints infinity and a 250 mm object-to-image close state at the wide, middle and tele stations. For close focus the L3–L8 block (L3 through L6 and the L7/L8 doublet) moves 5.7 mm toward the image while L1/L2 and the L9/L10 doublet stay fixed: D4 opens from 11.6 to 17.3 mm and D15 closes from 6.8 to 1.1 mm, the same at every zoom position, so the intermediate stations carry the same printed spacings. With the image plane held at its infinity-focus position, these spacings focus at about 249 mm object-to-image at the wide and tele stations and 247 mm at the middle station. The 250 mm patent state matches the production 0.25 m minimum focus distance.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | S-LAH51 (catalog equivalent; supplier unconfirmed) |
| L2 | Neg. Meniscus (2× Asph) | L-LAL13 (catalog equivalent; supplier unconfirmed) |
| L3 | Negative Meniscus | S-LAH58 (catalog equivalent; supplier unconfirmed) |
| L4 | Negative Meniscus | S-FPL51 (catalog equivalent; supplier unconfirmed) |
| L5 | Biconvex Positive | S-TIL1 (catalog equivalent; supplier unconfirmed) |
| L6 | Negative Meniscus | S-FPL51 (catalog equivalent; supplier unconfirmed) |
| L7 | Biconvex Positive | Unmatched (patent nd=1.55715, νd=40.90; no catalog equivalent) |
| L8 | Negative Meniscus | S-LAH58 (catalog equivalent; supplier unconfirmed) |
| L9 | Biconcave Negative | Unmatched (patent nd=1.71628, νd=54.33; no catalog equivalent) |
| L10 | Positive Meniscus | Unmatched (patent nd=1.87753, νd=35.66; no catalog equivalent) |
| L11 | Positive Meniscus | S-NSL36 (catalog equivalent; supplier unconfirmed) |
| L12 | Negative Meniscus | S-LAH58 (catalog equivalent; supplier unconfirmed) |
| L13 | Biconvex Positive | S-TIM2 (catalog equivalent; supplier unconfirmed) |
| L14 | Biconvex Positive | S-FPL51 (catalog equivalent; supplier unconfirmed) |
| L15 | Biconcave Negative | S-LAM3 (catalog equivalent; supplier unconfirmed) |
| L16 | Biconvex Positive (2× Asph) | S-FPL51 (catalog equivalent; supplier unconfirmed) |
| L17 | Biconcave Negative | S-LAH58 (catalog equivalent; supplier unconfirmed) |
| L18 | Biconvex Positive | S-FSL5 (catalog equivalent; supplier unconfirmed) |