JP1987-244010 A — Naoshi Okada, Hisashi Tokumaru
| 7 ELEMENTS / 6 GROUPS |
| 100mm f/2 |
| 1.0m MFD |
| FLOATING FOCUS |
| 9-BLADE DIAPHRAGM |
PUBLISHED — L1-L6 translate together relative to fixed L7 and the image plane; patent d11 increases from 0.880 mm at infinity to 16.339 mm at close focus (β ≈ -0.126).
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | 713539 — optical-glass coordinate class (vendor unresolved) |
| L2 | Positive Meniscus | S-LAL58 (OHARA catalog equivalent; patent 694518; production supplier unspecified) |
| L3 | Negative Meniscus | SF1 (SCHOTT catalog equivalent; patent 717294; production supplier unspecified) |
| L4 | Biconcave Negative | FD9 (HOYA catalog equivalent; patent 654337; production supplier unspecified) |
| L5 | Biconvex Positive | Unmatched (781446 high-index mid-dispersion glass; no compatible public coefficient row) |
| L6 | Biconvex Positive | S-LAH60 (OHARA catalog equivalent; patent 834371; production supplier unspecified) |
| L7 | Biconvex Positive | 720503 — optical-glass coordinate class (vendor unresolved) |