US 6,560,042 B2 Example 3 — Pentax / Murata, Ito
| 9 ELEMENTS / 7 GROUPS |
| f ≈ 31.8 mm |
| F/1.8 |
| 2ω ≈ 69.6° |
| 1 ASPHERICAL SURFACE |
Two-group differential-advance (floating) inner focus with non-linear cam. Fa (L1–L4) and Fb (L5–L9) advance toward object; Fb travels further, closing the Fa–Fb gap.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | TAC8 (HOYA) |
| L2 | Negative Meniscus | S-TIH14 (OHARA) |
| L3 | Negative Meniscus | S-PHM52 (OHARA) |
| L4 | Biconvex Positive | TAFD30 (HOYA) |
| L5 | Biconcave Negative | S-NSL3 (OHARA) |
| L6 | Biconvex Positive | S-LAH65 (OHARA) |
| L7 | Biconcave Negative | S-TIH53 (OHARA) |
| L8 | Biconvex Positive (1× Asph) | Lanthanum flint (728/403, uncertain vendor) |
| L9 | Biconvex Positive | S-LAH66 (OHARA) |
Detailed analysis available in the interactive viewer above.