US 3,076,383 — Walter Mandler, Erich Wagner
| 5 ELEMENTS / 4 GROUPS |
| f ≈ 89.8 mm |
| F/2.5 (FIXED) |
| 2ω = 27° (PATENT) |
| ALL SPHERICAL |
Unit focus: the lens has no helicoid and is moved as a whole by the projector mount or an adapter. Only the image-side gap changes. The 1.0 m object-to-image endpoint is a modeling choice, not a manufacturer minimum distance.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | N-SSK5 catalog equivalent (Schott; SSK5-type extra-dense barium crown, patent coordinate 658508; production melt unspecified) |
| L2 | Plano-Convex | N-SSK5 catalog equivalent (Schott; SSK5-type extra-dense barium crown, patent coordinate 658508; production melt unspecified) |
| L3 | Plano-Concave | SF5 catalog equivalent (Schott; dense flint, patent coordinate 673322; production melt unspecified) |
| L4 | Negative Meniscus | SF4 catalog equivalent (Schott; dense flint, patent coordinate 755275; production melt unspecified) |
| L5 | Biconvex Positive | K-SK18 catalog equivalent (Sumita; SK18-type dense barium crown, patent coordinate 639555; production melt unspecified) |