JP1981-119109 A — Yusuke Nanjo
| 9 ELEMENTS / 8 GROUPS |
| 28-47.55 mm DESIGN / 28-50 mm MARKETED |
| f/3.5-4.5 |
| 75°-47.6° SOURCE FIELD |
| ALL-SPHERICAL |
NO_INTERNAL_RECONSTRUCTION — the patent publishes infinity-focus zoom states only. The marketed 0.6 m minimum focusing distance is metadata; all authored focus pairs remain at their published infinity values.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | 569562 — BAC4 catalog equivalent (production supplier unspecified) |
| L2 | Negative Meniscus (concave to image) | 720502 — lanthanum crown class (vendor unresolved) |
| L3 | Negative Meniscus (concave to image) | 518590 — crown class (vendor unresolved) |
| L4 | Positive Meniscus (convex to object) | 673321 — dense flint class (vendor unresolved) |
| L5 | Biconvex Positive | 773496 — lanthanum high-index class (vendor unresolved) |
| L6 | Biconvex Positive | 569562 — BAC4 catalog equivalent (production supplier unspecified) |
| L7 | Biconcave Negative | 723380 — barium dense-flint class (vendor unresolved) |
| L8 | Negative Meniscus (concave to image) | 755275 — dense flint class (vendor unresolved) |
| L9 | Biconvex Positive | 773496 — lanthanum high-index class (vendor unresolved) |