US 4,666,260 Example 1 — Asahi Kogaku / Takayuki Itoh
| 10 elements / 9 groups |
| f = 199.98 mm design |
| F/4 |
| 2ω = 12.4° patent field |
| All-spherical |
| Fixed-rear extension macro focus |
Fixed-rear extension: the first lens group moves toward the object. The data varies surface 13 so that D13 + STO.d equals the patent d13 spacing.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | S-FSL5 (OHARA) / N-FK5 class |
| L2 | Biconvex Positive | S-FPL51 (OHARA) / FCD1 class ED |
| L3 | Positive Meniscus | S-FPL51 (OHARA) / FCD1 class ED |
| L4 | Negative Meniscus | BPM4 (OHARA legacy, 613/438 short flint) |
| L5 | Negative Meniscus | S-TIM3 (OHARA, 613/370 flint) |
| L6 | Positive Meniscus | S-LAL14 (OHARA) |
| L7 | Biconvex Positive | S-LAL59 (OHARA) |
| L8 | Positive Meniscus | S-TIH6 (OHARA) |
| L9 | Biconcave Negative | S-LAL8 (OHARA) / N-LAK8 class |
| L10 | Biconvex Positive | S-BSL7 (OHARA) / N-BK7 class |
Detailed analysis available in the interactive viewer above.