Longitudinal aberration

Longitudinal: color by depth

Longitudinal aberration puts each color's focus at a different distance, so it shows up everywhere including dead center. In front of focus the fringe runs purple, behind it green. This is the purple fringing around bright highlights.

Focus moves with color

in front of focus: purple rim

at focus: clean

behind focus: green rim

Same bright highlight at three depths. The rim flips from purple to green as you cross the focus.