A lens hood protects the object lens against the incident light, reflections from water, snow and other surfaces which reflect the light. Thanks to its use one can prevent photo artefacts formation. In conditions of adverse lighting (sources of lateral light) its use improves also the contrast of a photo. The visor functions also as protection of object lens against any mechanical damages, especially damages of the front lens.
The visor is fixed with the use of filter thread. It was made of high quality metal, internal part of the visor is properly blackened and crimped what additionally prevents the formation of reflections.