US 2,720,140, Example III — Günther Lange
| 5 ELEMENTS / 3 GROUPS |
| DESIGN f = 151.2 mm |
| DESIGN F/4 |
| ALL SPHERICAL |
The model stays at infinity. The patent prints no focus data, so no focus motion is modeled, and 1.4 m is the retail minimum focus distance, not a modeled state. The image plane is the computed paraxial focus, 81.02 mm behind the last surface; the patent prints no back focus. The patent's 14° half field reaches 37.91 mm on the image plane. The 39.6 mm corner of the 6x6 format lies at 14.59°, just beyond the printed field.
| Element | Type | Glass |
|---|---|---|
| LI | Positive Meniscus | BAF11 (SUMITA, coordinate equivalent) |
| LII | Biconvex Positive | SK16 (SCHOTT, coordinate equivalent) |
| LIII | Biconcave Negative | BASF8 (SUMITA, coordinate equivalent) |
| LIV | Biconvex Positive | BASF7 (SUMITA, coordinate equivalent) |
| LV | Negative Meniscus | F5 coordinate proxy (source nd=1.60140, νd=38.3; production glass unspecified) |