US 4,951,078 Embodiment 1 — Okada / Minolta
| 500 mm f/8 fixed |
| f = 495.97 mm patent EFL |
| f/7.07 area-equivalent annular design aperture |
| 5 groups / 7 elements incl. plug-in filter |
| All-spherical catadioptric Cassegrain |
Production lens minimum focus is 4.0 m. US 4,951,078 publishes only the infinity prescription, so close-focus optical spacings are not modeled.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | BSC7 / N-BK7 class (517/642) |
| M1 | Annular Mangin Primary Mirror | 670571 - lanthanum crown (catalog unresolved) |
| M2 | Mangin Secondary Mirror | BSC7 / N-BK7 class (517/642) |
| L3 | Positive Meniscus | LAC8 / N-LAK8 class (713/539) |
| L4 | Negative Meniscus | BSC7 / N-BK7 class (517/642) |
| L5 | Nearly Afocal Meniscus | 670571 - lanthanum crown (catalog unresolved) |
| L6 | Negative Meniscus | 670571 - lanthanum crown (catalog unresolved) |
Detailed analysis available in the interactive viewer above.