B+W 37mm Screw-In Folding Rubber Lens Hood #900

Lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended you also get the added benefit of some extra protection from accidental impact.

 

The B+W #900 lens hood is made out of a high-quality matte black rubber and folds down and protects against contrast-reducing, uncontrolled, stray light. It is designed to match the focal length of standard lenses (50mm).