US 2,627,204 A — Albrecht Wilhelm Tronnier
| 6 ELEMENTS / 5 GROUPS |
| f ≈ 50.0 mm |
| F/2.0 |
| 2ω ≈ 46.8° (35mm) |
| PATENT FIELD 55° |
| ALL SPHERICAL |
Reconstructed unit focus to an assumed 1 m object-to-image distance: all six elements and the stop move 2.766564 mm objectward. The patent tabulates infinity only; intermediate extension is interpolated.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | N-SK16 coordinate proxy (source nd=1.62139, νd=60.3; production supplier unspecified) |
| L2 | Positive Meniscus | K-LaK11 coordinate proxy (catalog nd=1.65830, νd=57.3; source 1.65953/57.0; supplier unspecified) |
| L3 | Negative Meniscus | SF2 coordinate proxy (source nd=1.64691, νd=33.9; production supplier unspecified) |
| L4 | Biconcave Negative | S-TIM6 coordinate proxy (catalog nd=1.636358, νd=35.391923; source 1.63652/35.5; supplier unspecified) |
| L5 | Biconvex Positive | LAC13 coordinate proxy (catalog nd=1.69350, νd=53.34; source 1.69347/53.5; supplier unspecified) |
| L6 | Biconvex Positive | S-BAH28 coordinate proxy (catalog nd=1.72342, νd=37.955602; source 1.72381/38.0; supplier unspecified) |