US 4,114,992, Embodiment 1 — Tadashi Kimura
| 5 ELEMENTS / 5 GROUPS |
| DESIGN f = 100 (NORMALIZED; SCALED 1.8× TO 180 mm) |
| DESIGN F/2.8 |
| ALL SPHERICAL |
Unit focus: Olympus specifies helicoid focusing to 2.0 m, so the whole optical block moves forward and only the back focus changes, by 19.95 mm at 2.0 m. The patent prints the infinity prescription only; the close-focus back focus is derived (paraxial solve for 2.0 m object to image, about 1:9) and is not a published state.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | S-BAH11 (OHARA catalog equivalent; production supplier unspecified) |
| L2 | Positive Meniscus | S-BSM15 (OHARA catalog equivalent; production supplier unspecified) |
| L3 | Positive Meniscus | S-BSM14 (OHARA catalog equivalent; production supplier unspecified) |
| L4 | Negative Meniscus | S-TIH11 (OHARA catalog equivalent; production supplier unspecified) |
| L5 | Positive Meniscus | S-TIH14 (OHARA catalog equivalent; production supplier unspecified) |