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Aperture Stops

Definition: apertures which limit the angular range of received input light of imaging systems

German: Öffnungsblenden, Aperturblenden

Categories: general optics, vision, displays and imaging

How to cite the article; suggest additional literature

The angular range from which an imaging system can receive light is always limited by some kind of optical aperture, which is called the aperture stop. The mentioned angular range is considered from the central point of the object plane, to which the instrument is focused. Different apertures can play the role of the aperture stop:

If an optical system contains multiple apertures, the aperture stop is that aperture which most severely limits the mentioned angular range.

The aperture stop sets a limit to the light gathering power of the instrument. It often needs to be reduced in order to avoid excessive optical aberrations which would occur for a larger opening angles.

See also: optical apertures, field stops, imaging, f-number, objectives, numerical aperture, entrance and exit pupil
and other articles in the categories general optics, vision, displays and imaging

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