JP 2020-122918 A — Hirokazu Shimada, Yasuyuki Sugano
| 7 ELEMENTS / 6 GROUPS |
| EFL 74.503 mm MODEL / 74.5 mm PATENT |
| 75 mm / f/1.5 MARKETED |
| F/1.54 / 2ω = 32.0° PATENT |
| 32.6° MARKETED AOV |
| 3 APD ELEMENTS (PATENT / MANUFACTURER) |
| 2 ASPHERICAL SURFACES |
CONSTRAINED_RECONSTRUCTION: rigid translation of the complete optical unit on the published helicoid; the patent gives only infinity data. The modeled rear image gap increases from 36.19 mm to 46.29933327830486 mm at the manufacturer's 0.7 m minimum focus, with all internal spacings unchanged.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | 729547 — lanthanum crown (vendor unresolved) |
| L2 | Positive Meniscus | 497816 — ED crown (vendor unresolved) |
| L3 | Positive Meniscus | 497816 — ED crown (vendor unresolved) |
| L4 | Negative Meniscus | 699301 — dense flint (vendor unresolved) |
| L5f | Biconcave Negative | 603380 — flint (vendor unresolved) |
| L5r | Biconvex Positive | 883408 — high-index lanthanum glass (vendor unresolved) |
| L6 | Biconvex Positive (2× Asph) | 516641 — borosilicate crown (vendor unresolved) |