US 4,726,669 — Pierre Angénieux
| 8 ELEMENTS / 6 GROUPS |
| f = 179.927 mm (DESIGN) |
| f/2.3 |
| 2ω = 13.6° |
| PUBLISHED COMPOUND FOCUS |
| ALL-SPHERICAL |
PUBLISHED compound internal focus using the patent's D2, D6, and D11 endpoints at infinity and β = −0.12. D2 contracts by 2.574 mm and D11 by 17.406 mm; the rounded D2+D6 totals leave a 0.018 mm coordinate residual, so Component IV shifts 17.424 mm relative to R1. The authored BF endpoint is the fixed-image-plane completion; the corresponding model object-to-image distance is 1.78865 m and the traced magnification is −0.120513.
| Element | Type | Glass |
|---|---|---|
| L1 | Biconvex Positive | SK5 (Sumita catalog equivalent to patent 589612; production supplier unspecified) |
| L2 | Positive Meniscus | S-FPL51 (OHARA catalog equivalent to patent 497816; production supplier unspecified) |
| L3 | Plano-Concave Negative | K-SFLD11 (Sumita catalog equivalent to patent 785259; production supplier unspecified) |
| L4 | Negative Meniscus | S-LAH66 (OHARA catalog equivalent to patent 772497; production supplier unspecified) |
| L5 | Positive Meniscus | S-LAH53 (OHARA catalog equivalent to patent 806409; production supplier unspecified) |
| L6 | Negative Meniscus | S-LAH66 (OHARA catalog equivalent to patent 772497; production supplier unspecified) |
| L7 | Negative Meniscus | S-TIH10 (OHARA catalog equivalent to patent 728284; production supplier unspecified) |
| L8 | Biconvex Positive | S-LAH66 (OHARA catalog equivalent to patent 772497; production supplier unspecified) |