US 3,883,229, Example II — Fritz Determann, Heinz Zajadatz
| 6 ELEMENTS / 6 GROUPS |
| DESIGN f = 249.20 mm |
| DESIGN F/5.6 |
| ALL SPHERICAL |
| 1 CaF₂ CRYSTAL ELEMENT |
Unit focusing: the whole optical unit moves forward on the Hasselblad V helicoid, so only the back focus changes. The patent gives only the infinity state. The close state is derived for the marketed 3.0 m object-to-film minimum, which needs 25.9 mm of extension and gives 1:9.62 (Zeiss: 1:9.6).
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | LaFN8 class (Schott, obsolete, 735416; patent "LaFN 8") |
| L2 | Biconvex Positive | CaF2 (calcium fluoride crystal; patent "Fluorspar") |
| L3 | Biconcave Negative | LaF20 class (Schott, obsolete, 682482; patent "LaF 20") ≈ LAFL20 (Hoya) |
| L4 | Positive Meniscus | FN11 class (Schott, obsolete, 621362; patent "F 11") ≈ TIM11 (OHARA) |
| L5 | Positive Meniscus | LaF20 class (Schott, obsolete, 682482; patent "LaF 20") ≈ LAFL20 (Hoya) |
| L6 | Biconcave Negative | LF8 class (Schott, obsolete, 564438; patent "LF 8") |