US 7,289,274 B1 Example 5 — PENTAX / Saori
| 18 ELEMENTS / 14 GROUPS |
| f = 51.5–131.0 mm (patent) / 50–135 mm (marketing) |
| F/2.8 (constant) |
| 3 ED ELEMENTS |
| ALL-SPHERICAL |
Internal focus (IF) via sub-group 10R (L4 + L5); constant travel ≈13.5 mm across all focal lengths.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | S-LAM2 (OHARA) |
| L2 | Positive Meniscus | S-FSL5 (OHARA) |
| L3 | Positive Meniscus | S-FPL51 (OHARA) |
| L4 | Negative Meniscus | S-TIH6 (OHARA) |
| L5 | Biconvex Positive | S-FSL5 (OHARA) |
| L6 | Biconcave Negative | S-LAH65V (OHARA) |
| L7 | Biconcave Negative | S-FSL5 (OHARA) |
| L8 | Positive Meniscus | S-TIH53W (OHARA) |
| L9 | Negative Meniscus | S-LAL18 (OHARA) |
| L10 | Biconvex Positive | S-LAH66 (OHARA) |
| L11 | Positive Meniscus | S-FPL51 (OHARA) |
| L12 | Negative Meniscus | S-TIH6 (OHARA) |
| L13 | Positive Meniscus | S-LAH66 (OHARA) |
| L14 | Biconvex Positive | S-FPL51 (OHARA) |
| L15 | Biconcave Negative | N-SSK5 (Schott-equivalent, nd=1.65844, νd=50.9) |
| L16 | Biconvex Positive | S-BAM4 (OHARA) |
| L17 | Negative Meniscus | S-LAM66 (OHARA) |
| L18 | Positive Meniscus | S-FSL5 (OHARA) |
Detailed analysis available in the interactive viewer above.