defocus

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defocus

(de-fo'kus) [L. de, away from, + focus, hearth]
The blurring of a visual image caused by spherical aberration, chromatic aberration, or diffraction. Also called optical defocus. Synonym: optical defocus

optical defocus

Defocus.

defocus

To put or go out of focus.
hyperopic defocus State of the eye in which the retinal image is focused behind the retina. It may occur when placing a negative lens in front of an emmetropic presbyopic eye; in an uncorrected presbyopic hyperope; in a high hyperope unable to overcome the ametropia by accommodating; or as an accommodative lag in an uncorrected or corrected myope, as well as in an emmetrope viewing a near object. See lag of accommodation; over-correction.
myopic defocus State of the eye in which the retinal image is focused in front of the retina. It may occur when placing a positive lens in front of an emmetropic eye; in an uncorrected or undercorrected myopic eye; or if there is a lead of accommodation, as is the case in some individuals viewing a distant object. See lead of accommodation; under-correction.
References in periodicals archive ?
In order to analyze the defocusing effect of the LLPEs, we shall assume that all single-look SAPs are defocused by the same LQPE [[beta].
Two defocused versions will be generated when the compensated patch is processed by an SDF pair.
When defocused, it provides supplemental infrared illumination.
It also raises an alarm when a camera is redirected, masked, sprayed, or defocused.
Using a high-resolution transmission electron microscope at LBL, the scientists took 20 pictures of lithium cobalt oxide--each one deliberately defocused a little differently--with a nearly atomic resolution of 1.
Surprisingly, older observers were better than younger ones in identifying defocused (optically blurred) text in both daytime and nighttime conditions.
Jack Gabzdyl, Product Line Manager for Pulsed Fiber Lasers, welcomed the release; "Lasers with low order modes prove to have high intensity in the central point, they can be defocused but the intensity issue remains.
BlackBerry CEO John Chen is obviously doing the Toronto company some good as the company changed business strategies and defocused on the mobile and tablet markets and instead shifted to pushing its popular Messenger app as it also released minor updates to its BB10 mobile operating system.
Professor Ilber Sela says that after 2006 when Gruevski changed the course of the identity and gave rise to populism and nationalism, the state politics was defocused from seeking a solution to the issue, which is a main condition for NATO and the EU.
The definition of CFZ assumes that the spot size of a defocused star (measured by its full-width at half-maximum intensity, or FWHM) becomes no larger than the Airy disk.
Apertures are used in the optical path of the laser to remove the defocused light rays, so that only focused images are displayed.
Earlier experiments had shown two major problems: Electrons were being emitted from the cathode so as to form an uneven electric field that drew the ions toward the cathode instead of sending them past it; and beyond the cathode, electrostatic fields were forming that defocused the ion beam.