Optical distortion is a serious problem, low-cost or high quality lenses produce distortion. This post explains the origins of these anomalies, how to reduce their results while shooting or using computer programmes.
Aberrations are caused by the shape and the design of a lens. These aberrations lead to optical distortion which does not affect so much some subjects, for example, landscapes. Optical distortion, instead, makes obvious in buildings or in highly geometric structures such as chess boards. The degree of distortion a lens produces does not depend on lens focal length: so we have the same grid pattern from 18mm up to 300mm. However, wide-angle lenses usually originate stronger optical distortion than tele-lenses.