Three of the main flaws are spots with undefined edges (usually caused by dust on the imaging sensor), color fringing around a highlight or Chromatic Aberration (usually cause by the lens or the lack of correction in the lens), and ghosting a type of lens flare (usually caused when shooting directly into the sun, the lack of or poor lens coatings designed to mitigate the effects of ghosting caused by a strong light source being reflected repeatedly within the lens)