Sigma LH780-03 Lens hood

A lens hood (also known as a lens shade) reduces stray light and aperture spots (lens reflections). This can significantly improve the image quality of photos in certain lighting situations. Lens reflections can occur when one or more strong light sources shine directly on the front lens of the lens, usually it is direct sunlight.

Depending on the construction and coating of the lens and the filters used, aperture spots or a reduction in contrast due to stray light can vary in intensity. The shape of lens flare depends on the shape of the aperture. In contrast to stray light, aperture spots do not always have a disturbing effect; they can also be used deliberately as a stylistic device for image composition.

A lens hood not only offers a reduction of the phenomena mentioned but also additional protection for the front lens or the screwed-in filter from damage.