US 3,912,373 — Karl Macher
| 31 ELEMENTS / 22 GROUPS |
| 20-600mm MARKETED; 20-592mm SOURCE STATIONS ×20 |
| MARKETED f/2.1-6.6 |
| ALL-SPHERICAL |
| TWO-STAGE 30× ZOOM |
Only infinity-focus zoom states are modeled; the patent describes L1 focusing without numerical travel. The 0.85 m close-focus value is secondary product metadata.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconcave Negative | N-LAK21 — native e-line compatible spectral proxy (supplier unresolved) |
| L2 | Biconcave Negative | N-LAK21 — native e-line compatible spectral proxy (supplier unresolved) |
| L3 | Biconvex Positive | N-SF8 — native e-line compatible spectral proxy (supplier unresolved) |
| L4 | Biconvex Positive | LAC12 — native e-line compatible spectral proxy (supplier unresolved) |
| L5 | Biconcave Negative | S-TIH23 — native e-line compatible spectral proxy (supplier unresolved) |
| L6 | Biconvex Positive | N-LAK21 — native e-line compatible spectral proxy (supplier unresolved) |
| L7 | Biconvex Positive | N-LAK21 — native e-line compatible spectral proxy (supplier unresolved) |
| L8 | Positive Meniscus | N-LAK21 — native e-line compatible spectral proxy (supplier unresolved) |
| L9 | Negative Meniscus | N-LAF21 — native e-line compatible spectral proxy (supplier unresolved) |
| L10 | Positive Meniscus | SF4 — native e-line compatible spectral proxy (supplier unresolved) |
| L11 | Biconcave Negative | N-LAK8 — native e-line compatible spectral proxy (supplier unresolved) |
| L12 | Positive Meniscus | SF1 — native e-line compatible spectral proxy (supplier unresolved) |
| L13 | Biconcave Negative | N-LAK8 — native e-line compatible spectral proxy (supplier unresolved) |
| L14 | Biconvex Positive | S-TIH18 — native e-line compatible spectral proxy (supplier unresolved) |
| L15 | Biconvex Positive | K10 — native e-line compatible spectral proxy (supplier unresolved) |
| L16 | Biconvex Positive | K10 — native e-line compatible spectral proxy (supplier unresolved) |
| L17 | Biconvex Positive | BSC3 — native e-line compatible spectral proxy (supplier unresolved) |
| L18 | Negative Meniscus | SF4 — native e-line compatible spectral proxy (supplier unresolved) |
| L19 | Positive Meniscus | SF4 — native e-line compatible spectral proxy (supplier unresolved) |
| L20 | Biconcave Negative | S-TIH10 — native e-line compatible spectral proxy (supplier unresolved) |
| L21 | Biconvex Positive | SF4 — native e-line compatible spectral proxy (supplier unresolved) |
| L22 | Biconcave Negative | N-LAF21 — native e-line compatible spectral proxy (supplier unresolved) |
| L23 | Biconcave Negative | N-LAF21 — native e-line compatible spectral proxy (supplier unresolved) |
| L24 | Biconvex Positive | N-FK5 — native e-line compatible spectral proxy (supplier unresolved) |
| L25 | Biconvex Positive | N-FK5 — native e-line compatible spectral proxy (supplier unresolved) |
| L26 | Negative Meniscus | N-SF8 — native e-line compatible spectral proxy (supplier unresolved) |
| L27 | Positive Meniscus | N-FK5 — native e-line compatible spectral proxy (supplier unresolved) |
| L28 | Negative Meniscus | N-LAF21 — native e-line compatible spectral proxy (supplier unresolved) |
| L29 | Biconcave Negative | N-LAF21 — native e-line compatible spectral proxy (supplier unresolved) |
| L30 | Biconvex Positive | N-FK5 — native e-line compatible spectral proxy (supplier unresolved) |
| L31 | Positive Meniscus | N-FK5 — native e-line compatible spectral proxy (supplier unresolved) |