US 7,656,591 B2, Example 1 — Hiroshi Yamamoto
| 9 ELEMENTS / 8 GROUPS |
| f ≈ 41.2 mm (design) · 45 mm (marketed) |
| F/2.8 |
| 2ω ≈ 72° (design image circle) · 51° (FX format) |
| ALL SPHERICAL |
| 1 ED ELEMENT |
CRC floating focus: G1+G3 move as a linked unit; G2 moves at a different rate. ΔD1 = −ΔD2 ≈ 4.28 mm. Maximum reproduction ratio 1:2 (β = −0.50).
| Element | Type | Glass |
|---|---|---|
| L11 | Negative Meniscus | S-LAH55V spectral proxy (OHARA; supplier unspecified) |
| L12 | Biconvex Positive | E-LAF11 catalog equivalent (production supplier not established; patent 757316) |
| L21 | Negative Meniscus | J-FKH1 spectral proxy (HIKARI; source 1.49782/82.56, supplier unspecified) |
| L22 | Biconvex Positive | N-LAF21 nonidentical spectral proxy (SCHOTT; source 1.78800/47.38, supplier unspecified) |
| L23 | Biconcave Negative | S-TIL26 nonidentical spectral proxy (OHARA; source 1.56732/42.72, supplier unspecified) |
| L31 | Biconvex Positive | S-PHM52Q spectral proxy (OHARA; supplier unspecified) |
| L32 | Biconcave Negative | SF1 spectral proxy (SCHOTT; supplier unspecified) |
| L33 | Positive Meniscus | N-FK5 spectral proxy (SCHOTT; source 1.48749/70.45, supplier unspecified) |
| L34 | Biconvex Positive | S-LAH65V spectral proxy (OHARA; supplier unspecified) |