US 4,235,521 EXAMPLE 1 — OLYMPUS / IMAI
| 6 ELEMENTS / 5 GROUPS |
| f ≈ 35.0 mm |
| F/2.8 |
| 2ω ≈ 63° |
| ALL SPHERICAL |
Coupled rangefinder focus, 0.85 m to infinity. Patent is infinity-only.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | S-LAH64 / N-LAF21 / TAF4 class (788/474) |
| L2 | Biconcave Negative | FD110 (HOYA) / S-TIH11 class (785/257) |
| L3a | Negative Meniscus | S-LAH63 / NBFD3 class (804/396) |
| L3b | Biconvex Positive | S-LAM61 class (720/460) |
| L4 | Negative Meniscus | S-LAH65 / TAF3 class (804/466) |
| L5 | Positive Meniscus | S-LAM7 / S-NBH51 class (750/353) |
Detailed analysis available in the interactive viewer above.