Ghost images are bright spots or reflections that appear in a camera viewfinder or on the final photograph, often taking the shape of the aperture. They typically occur when a lens is pointed toward a strong light source, such as the sun, and result from internal reflections within the lens elements.
Modern lenses with multi-layer coatings have largely minimized ghosting, improving image clarity and contrast. Understanding ghost images helps photographers recognize potential issues when shooting in bright conditions and take measures, such as using lens hoods or adjusting angles, to prevent unwanted reflections and maintain image quality.