Made of polished glass with ground edges.
Bi-convex lens: Magnifying or condensing lenses, with two outward curving symmetrical faces.
Diameter | Focal length (+) | Cat. No. |
38mm | 50mm | 3305-01 |
| 100mm | 3305-02 |
| 150mm | 3305-04 |
| 200mm | 3305-05 |
| 300mm | 3305-07 |
| 500mm | 3305-08 |
| 1000mm | 3305-09 |
50mm | 50mm | 3305-21 |
| 100mm | 3305-22 |
| 150mm | 3305-24 |
| 200mm | 3305-25 |
| 250mm | 3305-26 |
| 300mm | 3305-27 |
| 500mm | 3305-28 |
| 1000mm | 3305-29 |
75mm | 175mm | 3305-41 |
| 200mm | 3305-45 |