US 2,821,112 — Lautenbacher / Brendel, Enna-Werk
| 4 elements / 4 groups |
| f ≈ 35.0 mm |
| F/3.5 |
| 2ω ≈ 63.4° |
| all-spherical |
Unit focus; only the back-focus gap changes in the data model.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | Unmatched (518/652 crown class) |
| L2 | Plano-Convex Positive | N-LAF2 (Schott, equivalent) |
| L3 | Biconcave Negative | SF5 (Schott) |
| L4 | Biconvex Positive | N-LAK7 (Schott) |
Detailed analysis available in the interactive viewer above.