US 6,927,926 B2 — Takashi Kasahara, Masahiro Imamura
| 12 POWERED ELEMENTS / 10 AIR-SPACED GROUPS |
| DESIGN f ≈ 299.996 mm |
| TABLE F/2.80; PLOTS F/2.850 |
| NATIVE PUBLISHED FLOATING-FOCUS ENDPOINTS |
G2 moves toward the image and G3 toward the object for closer focus; G1 and G4 stay nominally fixed. The patent's near-focus state is approximately 2 m, compared with the production lens's 2.4 m minimum. Intermediate spacings are interpolated. Clear apertures are inferred, and some rays vignette near full aperture.
| Element | Type | Glass |
|---|---|---|
| L1 | Negative Meniscus | S-LAM7 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L2 | Biconvex Positive | S-FPL51 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L3 | Positive Meniscus | S-FPL51 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L4 | Negative Meniscus | S-LAH60 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L5 | Positive Meniscus | S-TIH53 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L6 | Negative Meniscus | S-BAM12 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L7 | Biconcave Negative | S-LAL14 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L8 | Negative Meniscus | S-LAM66 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L9 | Biconvex Positive | S-FPL51 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L10 | Biconcave Negative | S-TIL26 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L11 | Positive Meniscus | S-LAH53 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |
| L12 | Negative Meniscus | S-LAL14 (OHARA coordinate-compatible dispersion proxy; supplier unconfirmed) |