US 3,774,991, Example I — Yoshiyuki Shimizu
| 6 ELEMENTS / 4 GROUPS |
| f = 300.0 mm |
| F/4.5 |
| 2ω = 8.4° |
| ALL-SPHERICAL |
Infinity prescription only. The production lens focuses to 4 m by whole-lens movement; the patent supplies no finite-focus spacings.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | 486815 - fluophosphate crown class (vendor unresolved) |
| L2 | Biconcave Negative | 744449 - lanthanum glass class (vendor unresolved) |
| L3 | Positive Meniscus | 639450 - barium flint class (vendor unresolved) |
| L4 | Positive Meniscus | 486815 - fluophosphate crown class (vendor unresolved) |
| L5 | Biconcave Negative | 620603 - SK16-class crown (vendor unresolved) |
| L6 | Biconvex Positive | 620363 - F2-class flint (vendor unresolved) |