4GD Limited Lens 2

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4GD Limited Lens 2,ugg sale uk
Spherical aberration (spherical aberration) is, and others, such as non-point aberration and Coma (Coma aberration),Ugg Boots Australia, etc., as the image quality deterioration. Wherein the spherical aberration affecting the clarity of the screen most important factor, its production and the lens surface curvature, shape, and so on,Ugg Outlet, one lens structure can be combined by using a high refractive index or a non-spherical lens to minimize it, etc. , but still not designed to eliminate it. It deterioration of image effects can be imaged on the optical axis by the following description of examples, as shown, parallel to the optical axis of the light focused by the lens after simplifying the optical axis, through the aperture of the different incidence height (incidence height : a distance from the optical axis of incident light, said point a distance incidence height) of the light is not focused on the optical axis to a point on the ideal (paraxial image point), but the deviation of the respective focused on the optical axis of the ideal image point, paraxial image point is the hour when the aperture tends to clear image point ideal image point formed by the spherical aberration, the different incidence height and the each amount of deviation resulting drawn on the graph can be obtained that the lens of the spherical aberration if ideal image point on the right, the ball difference is positive, ideal image point in the left ball difference is negative. For a given lens, the incidence height of different aperture corresponds to a certain value equivalent to the aperture through the aperture edge of the light position, usually the longitudinal spherical aberration curve also be expressed as the aperture value. From a design point of view, I hope spherical aberration curves from side to side as small as possible, but unfortunately, with a straight curve characteristic of spherical aberration lens has not yet produced commercially if only literally, then, that the ideal Correction is totally corrected way, right? In actual fact, it usually takes the form of the lens which is it? First, let us look at several examples of famous portrait lens it. Below focuses at infinity Nikkor Ais 85/1.4, Planar T 85/1.4 and SummiluxM 75/1.4 measured spherical aberration curves are based on the latter two can be seen over-correction mode, which means that when you open the aperture through aperture edges (with a larger incidence height) of the light focused on the rear side of the paraxial image point, i.e. the rear side of the film; hole through light rays closer to the optical axis (with a low incidence height) is focused paraxial image point on the front side,Ugg Boots Australia, or near it, then the whole image by a collection of these rays constituted, image clarity is not satisfactory, the main undesirable components of the light from the optical edge of the hole when the aperture is clever after such 2 file level, then the height of a big incident light is blocked by the spherical aberration of it to disappear; but only in low-light imaging position on the film,ugg boots uk sale, the best image point is close to the paraxial image point, only the spherical aberration there is a small margin in the vicinity of the paraxial image point swing to obtain clear images.
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