US 4,666,259 A — Example 1 / Yutaka Iizuka, Nippon Kogaku
| 6 elements / 6 groups |
| f = 499.482 mm |
| F/6.7 geometric; f/8 effective |
| 2ω = 5° |
| all-spherical Mangin catadioptric |
Front-unit focus: L1 and M2 move together 8.05 mm toward the object; the rear mirror/corrector block and image plane remain fixed.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | BSC7 / N-BK7 class crown (patent 517/641) |
| M1 | Positive Mangin Mirror | BSC7 / N-BK7 class crown (patent 517/641) |
| M2 | Negative Mangin Mirror | BSC7 / N-BK7 class crown (patent 517/641) |
| L21 | Near-Plano-Concave Negative | BSC7 / N-BK7 class crown (patent 517/641) |
| L22 | Negative Meniscus | E-C3 (HOYA) / S-NSL3 class crown (518/590) |
| L23 | Positive Meniscus | Unmatched (lanthanum dense flint, patent 796/410; nearest current class S-LAH52 / K-LaSFn3) |
Detailed analysis available in the interactive viewer above.