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In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image.It is a form of optical aberration that may be distinguished from other aberrations such as spherical aberration, coma, chromatic aberration, field curvature, and astigmatism in a sense that these impact the image sharpness without changing an ...
In photography, a rectilinear lens is a photographic lens that yields images where straight features, such as the edges of walls of buildings, appear with straight lines, as opposed to being curved. In other words, it is a lens with little or no barrel or pincushion distortion. At particularly wide angles, however, the rectilinear perspective ...
Fig. 3a: Barrel distortion Fig. 3b: Pincushion distortion. Even if the image is sharp, it may be distorted compared to ideal pinhole projection. In pinhole projection, the magnification of an object is inversely proportional to its distance to the camera along the optical axis so that a camera pointing directly at a flat surface reproduces that ...
PC Magazine reports 3.1% distortion at 8 mm and 0.7% at 12 mm. [8] It also reports that distortion switches to pincushion distortion of 1.4% at 16 mm. [8] SLAR Gear reports that the point of convergence between barrel and pincushion is about 13 mm. [3] Foreground subjects seem abnormally large compared to similar background subjects with this ...
The perceptual barrel distortion is sufficiently small to be unnoticeable in everyday life. However, if a rectilinear magnifying optical instrument is panned over a flat motif, the image pixels pass in front of the eye in rapid succession and the visual barrel distortion becomes visible as an apparent convex curvature of the image.
Ultra-wide angle lenses come in two varieties: Fisheye lenses with curvilinear barrel distortion, and rectilinear lenses which are designed so that straight lines in the scene will render straight (uncurved) in the photographic image and thus lack the extreme distortion that is characteristic of a fisheye lens. Neither denotes a particular ...
For example, a greater degree of barrel and pincushion distortion is tolerated in lenses that span the focal length range from wide angle to telephoto with a focal ratio of 10× or more than would be acceptable in a fixed focal length lens or a zoom lens with a lower ratio. Although modern design methods have been continually reducing this ...
The mood effect of perspective distortion achieved by rectilinear extreme wide-angle lenses is that the resulting image looks grotesque and unsettling, while not looking as unrealistic as curvilinear fisheye lenses which display barrel distortion. The effect is especially noticeable the closer the camera is to the subject, as its amount ...