US 3,410,632 — Walter Wöltche
| 7 ELEMENTS / 6 GROUPS |
| f ≈ 35.2 mm |
| F/4 |
| 2ω ≈ 78° (57 mm IMAGE CIRCLE) |
| SHIFT ±7 mm |
| ALL SPHERICAL |
Unit focus (reconstruction): the complete optical unit is assumed to translate on the helicoid, so only the back focal distance changes. The patent publishes only the infinity state; the 0.30 m close-focus spacing (+6.15 mm extension, about 1:5.7) is solved from the manufacturer's closest distance measured from the film plane and is not a published conjugate.
| Element | Type | Glass |
|---|---|---|
| L1 | Plano-Convex | N-SK16 spectral proxy (Schott; native e-line dense-crown coordinates; supplier unconfirmed) |
| L2 | Negative Meniscus | N-BK7 spectral proxy (Schott; native e-line borosilicate-crown coordinates; supplier unconfirmed) |
| L3 | Biconvex Positive | BASF7 spectral proxy (Schott; native e-line BaSF52-type coordinates; supplier unconfirmed) |
| L4 | Positive Meniscus | Unmatched (historical BaSF13-type e-line coordinate; no verified compatible catalog curve) |
| L5 | Biconcave Negative | BAFD14 spectral proxy (HOYA; native e-line BaSF14-type coordinates; supplier unconfirmed) |
| L6 | Biconvex Positive | N-SK16 spectral proxy (Schott; native e-line dense-crown coordinates; supplier unconfirmed) |
| L7 | Positive Meniscus | LAC13 spectral proxy (HOYA; native e-line lanthanum-crown coordinates; supplier unconfirmed) |