JP 2004-101739 A — Tamron / Yamada Yasuharu
| 28-75mm f/2.8 |
| 16 elements / 14 groups |
| 4 hybrid aspherical surfaces |
| Internal focus by G2 |
| 0.33 m MFD |
Inner focus by movement of G2 only. Close-focus spacings are solved from a 0.33 m image-plane-referenced object distance; the patent gives infinity-focus zoom positions only.
| Element | Type | Glass |
|---|---|---|
| L11 | Negative Meniscus | S-TIH53 (OHARA) |
| L12 | Biconvex Positive | S-LAL14 (OHARA) |
| L13 | Positive Meniscus | S-LAH66 (OHARA) |
| L21R | Hybrid Aspherical Resin Layer | Unmatched hybrid aspheric resin (nd=1.53610, νd=41.2) |
| L21 | Negative Meniscus | S-LAH65V (OHARA) |
| L22 | Biconcave Negative | S-LAH65V (OHARA) |
| L23 | Biconvex Positive | S-TIH6 (OHARA; SF6 class) |
| L24 | Biconcave Negative | S-FSL5 (OHARA) |
| L25 | Biconvex Positive | S-TIH6 (OHARA; SF6 class) |
| L31 | Positive Meniscus | S-FPL51 (OHARA) / FCD1 class |
| L32R | Hybrid Aspherical Resin Layer | Unmatched hybrid aspheric resin (nd=1.53610, νd=41.2) |
| L32 | Positive Meniscus | S-FSL5 (OHARA) |
| L33 | Positive Meniscus | S-FPL51 (OHARA) / FCD1 class |
| L34 | Negative Meniscus | S-TIH53 (OHARA) |
| L41 | Positive Meniscus | S-FSL5 (OHARA) |
| L42 | Biconvex Positive | S-FPL51 (OHARA) / FCD1 class |
| L43 | Biconcave Negative | S-LAH60V (OHARA) |
| L43R | Hybrid Aspherical Resin Layer | Unmatched hybrid aspheric resin (nd=1.53610, νd=41.2) |
| L44 | Biconvex Positive | S-TIL25 (OHARA) |
| L44R | Hybrid Aspherical Resin Layer | Unmatched hybrid aspheric resin (nd=1.53610, νd=41.2) |
Detailed analysis available in the interactive viewer above.