Lens flare are unwanted artifacts caused by internal reflection and scattering of sun rays inside the lens. It appears when the sun is near or within the shot angle.
How do I remove it ?
Please note that the techniques I suggest should work for limited-sized flares. Widespread or nested flares usually are beyond help.
Lens flare can be observed in two shapes : small colored bright artefacts, and low-contrast circles or hazes.
The small artefacts are better removed using the clone stamp tool.
Circles and hazes are a bit more tricky but can usually be managed by retrieving the right color and contrast within the damaged zone.
In order to do this, select an area a bit larger than the flare. Copy the area in a new layer.
Bind a color-balance filter to this new layer and try to adjust to the color to find back the surrounding tones. Then add a contrast filter layer on top of that and adjust it to find back the surrounding contrast.
Then choose a soft brush approximately the size of the artefact and carefully erase the outer edge without revealing it.
A few adjustments may be necessary to get the maximum blending, but in the end the original artefact should be barely noticeable.
– Beware of the sun orientation
If you can, regarding your desired composition, avoid shooting facing the sun. It will protect your gear from potential damage and prevent you from dealing with back light.
– Use a lens hood
For each lens, constructors provide with a hood to be mounted to your front lens. It is specially designed to reduce flare caused by light coming sideways. It cannot stop you from shooting facing the sun though !
– Invest in better lens
The cheaper the lens, the cheaper the materials composing it. A better quality lens is built with improved glass and special coating which greatly reduce image aberrations.