Glossary |
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| Nano Crystal Coat | Nano Crystal Coat is an antireflective coating that originated in the development of NSR-series (Nikon Step and Repeat) semiconductor manufacturing devices. It virtually eliminates internal lens element reflections across a wide range of wavelengths, and is particularly effective in reducing ghost and flare peculiar to ultra-wideangle lenses. Nano Crystal Coat employs multiple layers of Nikon’s outstanding extra-low refractive index coating, which features ultra-fine crystallized particles of nano size (one nanometer equals one millionth of a mm). Nikon now proudly marks a world first by applying this coating technology to a wide range of lenses for use in consumer optical products. |
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| Near-sightedness | The eye condition in which the image of an infinitely distant point is formed in front of the retina when the eye is in the accommodation rest state. |
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| Normal vision, emmetropia | The eye condition in which the image of an infinitely distant point is formed on the retina when the eye is in the accommodation rest state. |
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| Numerical aperture (NA) | A value used to express the brightness or resolution of a lens\' optical system. The numerical aperture, usually indicated as NA, is a numerical value calculated from the formula nsin¸, where 2¸ is the angle (angular aperture) at which an object point on the optical axis enters the entrance pupil and n is the index of reflection of the medium in which the object exists. Although not often used with photographic lenses, the NA value is commonly imprinted on the objective lenses of microscopes, where it is used more as an indication of resolution than of brightness. A useful relationship to know is that the NA value is equal to half the inverse of the F number. For example, F 1.0 = NA 0.5, F 1.4 = NA 0.357, F2 = NA 0.25, and so on. |
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