lensmeter

thumb|right|A lensmeter in an optical shop thumb|right|upright|A simple lensmeter cross sectional view.

1 – Adjustable eyepiece 2 – Reticle 3 – Objective lens 4 – Keplerian telescope 5 – Lens holder 6 – Unknown lens 7 – Standard lens 8 – Illuminated target 9 – Light source 10 – Collimator 11 – Angle adjustment lever 12 – Power drum (+20 and -20 diopters) 13 – Prism scale knob