PRO TECHNIQUE
AVOID A FLARE-UP
If any light source hits the front element of a lens directly, it will bounce around inside the internal elements, reducing contrast and possibly causing flare within the image. Flare can be creatively attractive, of course – but only if you want it!
Many lenses come with a hood (which sometimes costs extra) that shades the front element without appearing in the shot. Prime lenses have deeper, more cylindrical hoods, while wide to medium zooms have petal-shaped hoods. Hoods should always be used if you want to keep flare out and ensure image quality.