- In the backlight, side light or flash photography, to prevent the non-imaging light to enter, to avoid haze
- Shades the lens from stray light, improving your contrast and image quality.
- Bayonet mount design makes it firmly on the lens.
- Can prevent accidental damage to the lens, but also to avoid finger contact with the lens surface.
Blocks stray light from entering the lens, supply extra protection from accidental impact.