 thumbnail|right|this simulation shows how adjusting the angle of view of a camera, while varying the camera distance, keeping the object in frame, results in vastly differing images. at narrow angles, large distances, light rays are nearly parallel, resulting in a "flattened" image. at wide angles, short distances, the object appears distorted. in photography and cinematography, perspective distortion is a warping or transformation of an object and its surrounding area that differs significantly from what the object would look like with a normal focal length, due to the relative scale of nearby and distant features. perspective distortion is determined by the relative distances at which the image is captured and viewed, and is due to the angle of view of the image (as captured) being either wider or narrower than the angle of view at which the image is viewed, hence the apparent relative distances differing from what is expected. related to this concept is axial magnification -- the perceived depth of objects at a given magnification. perspective distortion takes two forms: extension distortion and compression distortion, also called wide-angle distortion and long-lens or telephoto distortion,mark galer, photography foundations for art and design, page 73 when talking about images with the same field size. extension or wide-angle distortion can be seen in images shot from close using a wide-angle lens (with an angle of view wider than a normal lens). object close to the lens appears abnormally large relative to more distant objects, and distant objects appear abnormally small and hence more distant â distances are extended. compression, long-lens, or telephoto distortion can be seen in images shot from a distant using a long focus lens or the more common telephoto sub-type (with an angle of view narrower than a normal lens). distant objects look approximately the same size â closer objects are abnormally small, and more distant objects are abnormally large, and hence the viewer cannot discern relative distances between distant objects â distances are compressed. note that linear perspective changes are caused by distance, not by the lens per se â two shots of the same scene from the same distance will exhibit identical perspective geometry, regardless of lens used. however, since wide-angle lenses have a wider field of view, they are generally used from closer, while telephoto lenses have a narrower field of view and are generally used from farther away. for example, if standing at a 
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