US 4,018,512 — Yutaka Sakai
| 8 elements / 6 groups |
| 35mm |
| f/1.9 |
| 63° patent field |
| all-spherical |
Unit focus; patent publishes only the infinity prescription, so close-focus travel is approximated from the 0.40 m production minimum-focus specification.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | S-BSL7 (OHARA catalog-equivalent) |
| L2 | Biconvex Positive | S-LAH66 (OHARA catalog-equivalent) |
| L3 | Positive Meniscus | S-LAM52 / J-LAF02 class (catalog-equivalent; patent nd rounded) |
| L4 | Biconcave Negative | H-BaF8 (CDGM catalog-equivalent) |
| L5 | Biconcave Negative | S-TIM35 (OHARA catalog-equivalent) |
| L6 | Biconvex Positive | S-LAL14 (OHARA catalog-equivalent) |
| L7 | Positive Meniscus | S-LAL14 (OHARA catalog-equivalent) |
| L8 | Positive Meniscus | S-LAL14 (OHARA catalog-equivalent) |