Microscope No. 244 comes with three bi-convex objective lenses. They are mounted in a brass base, with the threads on both the inside and outside surfaces. This allows the lenses to be screwed together to increase the magnification.
Lens
Dia (mm)
f (mm)
Magnification
1
6
30
6x
2
8
34
6x
3
14
40
4.5x
Lens grouping
f (mm)
Magnification
1+2
14
12x
1+3
14
12x
2+3
16
15x
1+2+3
7
20x