US 2019/0265441 A1 EXAMPLE 2 — CANON / KATAYOSE
| 15 ELEMENTS / 9 GROUPS |
| f ≈ 51.1 mm (marketed 50 mm) |
| F/1.25 (marketed F/1.2) |
| 2ω ≈ 45.9° |
| 3 ASPHERICAL SURFACES |
| 1 UD ELEMENT (S-FPL51) |
Front-group extension focus: L1 (G1–G11 + stop) translates toward object; L2 (G12–G15) stationary. Single variable gap (d19); BFD constant. Ring-type USM.
| Element | Type | Glass |
|---|---|---|
| G1 | Biconvex Positive (1× Asph) | S-LAH65V (OHARA) |
| G2 | Biconcave Negative | S-TIM28 (OHARA) |
| G3 | Positive Meniscus | S-NPH7 (OHARA) |
| G4 | Negative Meniscus | S-TIL27 (OHARA) |
| G5 | Biconcave Negative | 666356 — dense flint (nd=1.66565, νd=35.64) |
| G6 | Positive Meniscus | 954323 — ultra-high-index dense flint (nd=1.95375, νd=32.32) |
| G7 | Positive Meniscus | S-FPL51 (OHARA) |
| G8 | Biconcave Negative | 738323 — niobium dense flint (nd=1.73800, νd=32.26) |
| G9 | Biconvex Positive | 764485 — lanthanum crown (nd=1.76385, νd=48.51) |
| G10 | Biconcave Negative | 666356 — dense flint (nd=1.66565, νd=35.64) |
| G11 | Biconvex Positive (1× Asph) | S-LAH58 / TAFD30 class (883408) |
| G12 | Biconvex Positive | S-LAH58 / TAFD30 class (883408) |
| G13 | Biconcave Negative | S-TIM1 (OHARA) |
| G14 | Biconcave Negative | S-NBH52 (OHARA) |
| G15 | Biconvex Positive (1× Asph) | S-LAH65V / L-LAH65V (OHARA) |
Detailed analysis available in the interactive viewer above.