Free from chromatic and spherical aberration; -- said esp. of a lens in which rays of three or more colors are brought to the same focus, the degree of achromatism thus obtained being more complete than where two rays only are thus focused, as in the ordinary achromatic objective.
corrected for both chromatic and spherical aberration; "an apochromatic lens"
A lens combination in which chromatic aberration is corrected by bringing three colours to the same focus. Some manufacturers use the term to describe achromatic doublets whose false colour is approximately equivalent to that of an apochromatic triplet lens.
An apochromatic telescope uses three or more lens elements, one or more usually possessing special properties, to eliminate chromatic aberration. Apochromatic refractors are usually regarded as giving the best quality image but are by far the most expensive type of telescope for a given size.
In photography, color-corrected lenses that focus the three colors, blue, green and red, on the same plane.
Refers to lenses designed to correct for chromatic (color) aberrations. Usually used in telephoto lenses that have large maximum apertures.
An optical system without color aberration and free of secondary spectrum.
In photography, color-corrected lenses which focus the three colors, blue, green and red, in the same plane.
A highly color corrected lens system. Note that this is an over simplified definition.
A lens that is corrected for both chromatic and spherical aberrations.
A lens system that brings all three primary colours to the same point of focus, and is thus considered free of chromatic aberration. (Some consider that a true apochromatic lens ought to eliminate spherical aberration also.).
Lens corrected for chromatic aberrations in all three primary colours. Many manufactures use different names (i.e. NIKON use ED)
A type of lens comprised of three elements of different materials, which has the effect of bringing most colors to a focus, thus reducing chromatic aberration. A step up from achromatic lenses.
often shortened to "APO," means corrected for spherical and chromatic aberration. Lenses that are apochromatic cause all visible light wavelengths to focus on the film plane. Lenses that are not corrected for chromatic aberration tend to focus red, green and blue wavelengths on different planes.
Apo -- A term used to describe optics. Generally it means excellent quality with no color distortion and no aberrations. Very commonly used to describe top quality (i.e. expensive) refracting telescopes.
In photography, colour-corrected lenses, which focus the three, colours, blue, green and red, in the same plane.