In photography, a camera lens which has been modified to reduce or eliminate chromatic aberration by focusing two different colors (such as blue-violet and yellow) simultaneously. Chromatic aberration, which manifests itself as a blurring of colors, is caused by the refraction of light of different wavelengths (colors) as it passes through a curved lens and strikes a flat photographic plate or emulsion. By grinding a lens so that two prominent colors are in common focus, the blurring effect can be minimized. Achromat lenses are found in nearly all cameras these days. Achromat lenses are also referred to as apochromatic.
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