Lateral Chromatic Aberration
Colour fringing caused by different wavelengths being magnified by slightly different amounts, appearing as coloured edges toward the frame corners.
Measured in
pixels
In depth
Because the error is a difference in magnification rather than focus, it is absent at the centre and grows steadily toward the edges, showing as cyan-red or blue-yellow fringes along high-contrast boundaries. It is a purely geometric error, which means software can correct it almost perfectly by rescaling the individual colour channels.
Examples in practice
Bare tree branches against a bright sky show red fringes on one side and cyan on the other near the frame edge.