pincushionförvrängning

Pincushion distortion is a type of optical distortion where straight lines that are supposed to be parallel appear to bow inwards towards the center of the image. This effect is commonly seen in wide-angle lenses and is characterized by the image appearing compressed or "pinched" in the center, resembling the shape of a pincushion. The opposite of pincushion distortion is barrel distortion, where straight lines bow outwards.

The phenomenon is caused by the way light rays are refracted as they pass through the lens elements. In simpler terms, the lens does not magnify the edges of the image as much as it magnifies the center. This results in the edges of the scene being squeezed inwards. Factors such as the focal length of the lens, the design of the lens elements, and the distance to the subject can influence the degree of pincushion distortion.

While often considered an undesirable artifact, pincushion distortion can sometimes be intentionally employed by photographers for artistic effect, such as to make a subject appear closer or to create a specific visual style. Fortunately, pincushion distortion can be corrected in post-processing using image editing software. Many programs offer tools that can automatically detect and reduce or eliminate this type of distortion, restoring straight lines to their intended form.