Optically worked, back silvered, with protective coating.
| Type |
A |
B |
C |
D |
E |
F |
| Focal Length (mm) |
75 |
100 |
150 |
200 |
250 |
300 |
| Diameter 50 mm |
75 |
100 |
150 |
200 |
250 |
300 |
| Diameter 75 mm |
75 |
100 |
150 |
200 |
250 |
300 |
