JP S30-4837 B — Ludwig Bertele
| 7 ELEMENTS / 4 GROUPS |
| f ≈ 34.75 mm |
| F/2.8 |
| 2ω ≈ 64° |
| ALL SPHERICAL |
Unit focus: the whole optical unit moves on the lens's own helicoid, coupled to the Contax rangefinder. The patent gives only the infinity state; the 0.9144 m (3 ft) close-focus extension of about 1.44 mm is a paraxial reconstruction.
| Element | Type | Glass |
|---|---|---|
| L1 | Positive Meniscus | K-SSK4 (Sumita) / SSK4 class (618551) |
| L2 | Biconvex Positive | J-BASF2 class (Hikari; supplier unconfirmed) |
| L3 | Biconcave Negative | SF3 (Schott) (740282) |
| L4 | Biconcave Negative | FK3 class (Schott; historical supplier unconfirmed) |
| L5 | Biconvex Positive | N-SK16 (Schott) / SK16 class (620603) |
| L6 | Positive Meniscus | N-SK16 (Schott) / SK16 class (620603) |
| L7 | Negative Meniscus | FK3 class (Schott; historical supplier unconfirmed) |