Position the focimeter at a comfortable angle for viewing by using the locking lever or inclination control at the side of the instrument (Figure 1, label 10) to adjust the tilt of the focimeter. This is also a good time to ensure the prism compensator is at 0.

It is essential to focus the eyepiece for your eye if someone else has used the focimeter before you. The video in the Multimedia Tab of this article called 'Setting up a Focimeter' demonstrates how to focus the eyepiece. The steps are:

Rotate the eyepiece counter-clockwise until the reticle is blurred. A white card or piece of paper held behind the eyepiece may make the reticle lines more visible.