US 3,632,190 Example 1; folded Mangin catadioptric
| 500 mm nominal focal length |
| f/8 marketed, F/7 geometric prescription |
| 5 elements / 3 groups |
| 5° diagonal field |
| manual fixed-aperture mirror lens |
Manual front-cell focus in the production lens; the patent publishes only the infinity spacing, so finite-focus variable gaps are not modeled.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | Unmatched light crown (525/596; K5-class nearest) |
| M2 | Convex Secondary Mangin Mirror | LLF1 / S-TIL1 / E-FEL1 class (548/459) |
| L2 | Plano-Concave Negative | BAK4 / BAC4 class (569/560) |
| L3 | Plano-Convex Positive | SF10 / E-FD10 / S-TIH10 class (728/283) |
| M1 | Annular Concave Mangin Mirror | LLF2 / S-TIL2 / E-FEL2 class (541/472) |
| L4 | Negative Meniscus | LLF2 / S-TIL2 / E-FEL2 class (541/472) |
Detailed analysis available in the interactive viewer above.