JP 2021-85935 Example 1 — Sigma / 塩田 了 (Ryo Shioda)
| 15 ELEMENTS / 11 GROUPS |
| f ≈ 82.96 mm (design) |
| F/1.4 (F/1.46 design) |
| 2ω ≈ 28.12° |
| 1 BIASPHERIC ELEMENT (L15) |
Inner focus by single negative meniscus L7 (G2 / LF). L7 translates rigidly toward the image at close focus over a 9.6026 mm throw. Stepping-motor drive (Sigma published spec); BFD held constant.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | Dense LPH flint (νd=17.98; high g-line anomalous dispersion) |
| L2 | Positive Meniscus | Fluorophosphate SLD (FCD705-class, νd=75.5) |
| L3 | Positive Meniscus | Fluorophosphate SLD (FCD705-class, νd=75.5) |
| L4 | Positive Meniscus | Phosphate SLD class (νd=68.6) |
| L5 | Negative Meniscus | Anomalous flint (S-NBH8-class, νd=25.15) |
| L6 | Positive Meniscus | Phosphate SLD class (νd=68.6) |
| L7 | Negative Meniscus | SLD-class crown (νd=67.0) |
| L8 | Negative Meniscus | Anomalous flint (S-NBH8-class, νd=25.15) |
| L9 | Positive Meniscus | Phosphate SLD class (νd=68.6) |
| L10 | Biconcave Negative | Anomalous flint (S-NBH8-class, νd=25.15) |
| L11 | Biconvex Positive | TAFD-class lanthanum-niobate (νd=29.13) |
| L12 | Biconvex Positive | Ultra-dense flint (νd=26.94) |
| L13 | Biconcave Negative | Moderate flint (νd=30.05) |
| L14 | Biconvex Positive | TAFD-class lanthanum-niobate (νd=29.13) |
| L15 | Biconcave Negative (2× Asph) | Moldable lanthanum dense crown (L-LAM-class, νd=40.5) |
Detailed analysis available in the interactive viewer above.