Students measured chromatic aberration using an optical bench. A standard target pattern was projected through the test lens and imaged using a CCD camera. The difference in position between focus with green light and focus with red light gave a measure of the aberration.

Optical bench. A: Light source with test pattern; B: Test optic holder; C: Imaging objective with micrometer position adjust.

Modern objective (L) collects light projected through the test optic (Pyefinch objective).

Finding the initial focus position of the test optic.

Imaging the test pattern using monochromatic light.