US 2,995,980 — ZIMMERMANN & KNETSCH / ERNST LEITZ
| 5 ELEMENTS / 3 GROUPS |
| f ≈ 90.1 mm |
| F/2.8 |
| 2ω ≈ 27.0° |
| ALL SPHERICAL |
Unit focusing — entire optical assembly translates forward via helicoid. Detachable head for Visoflex use.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | LaK9 (SCHOTT) |
| L2 | Positive Meniscus | SF4 (SCHOTT) |
| L3 | Biconcave Negative | 1640/346 (F-family flint) |
| L4 | Biconcave Negative | BaSF1 (SCHOTT) |
| L5 | Biconvex Positive | LaF2 (SCHOTT) |
Detailed analysis available in the interactive viewer above.