This can happen when taking a picture under a strong light source where excessive light is entering the lens. The strong light is reflected onto the sensor by the glass and optical elements inside the lens. It is more likely to occur when shooting toward a bright light or the sun.
Using a lens hood or polarizing filter may help reduce ghosting and flare. Keep in mind, however, it may not be possible to completely eliminate ghosting and lens flare depending on where you are aiming the camera.
IMPORTANT: Using a polarizing filter reduces the amount of light that reaches the camera sensor. The amount of light reduction is typically 2 or 3 F-stops. Since there is less light entering the camera, this can increase the possibility of blur when doing handheld photography - especially if trying to capture action shots.
- Lens flare and ghosting can appear as bright streaks, arcs, blurs, or rainbow circles of light.
- Some photographers use ghosting and lens flare to their advantage for creating unique photo compositions.