The optics of the drum microscope consists of three lenses:
Eyepiece: Bi-convex, Dia = 1.5cm, f=3.4cm
Field: Bi-convex, dia=2.5cm, f=5.0cm
Objectives (2, bi-convex):
|
Obj
|
dia (mm)
|
f(mm)
|
aperture
|
|
2
|
5.0
|
9
|
2
|
|
3
|
5.0
|
5
|
1.5
|
The field lens is held into the tube body by a metal retaining ring.
There are two objectives, labeled "2" and "3".