The compound body consists of the typical three lenses. A: Objective; B: Field lens (dia=2.4cm, f=19cm); C: eyelens (dia=1.1cm, f=2.8cm. Distance between eye and field lenses = 5.0cm.
Two low-magnification objectives for simple mode, and one high-magnification objective for compound mode. All objective lenses are 8mm in diameter.

A: f=7mm, aperture=4mm
B: f=16mm, aperture=6mm
C: f=3mm, aperture=4mm. This is a Coddington objective.