Wort des Tages
20 March 2026
achromatic lens
A lens generally composed of two separate lenses, one convex and one concave and generally of different materials, in such a way that the chromatic aberration produced by one is corrected by the other.
Warum dieses Wort
The name is Greek for "without colour," though it oversells: a two element achromat brings only two wavelengths to a common focus, and the usual fix is pairing crown glass with denser flint.
In use
The purple edges on the part outline went away as soon as we swapped the singlet for an achromatic lens.
Written by our editors to show how the term is used, not a recorded quotation.