Star filters create multiple points of light, or "stars," streaking outward from a central light source. This can make lighting within the scene take on a more glittering, glamorous appearance. This effect is produced by a series of thin lines etched into the flat optical surface of a clear filter. The size and brightness of the star lines produced are first a function of the size, shape, and brightness of the light source. Lines in one direction produce a two-pointed star, just a streak through the center of the light. Cokin offers 4,8, and 16 point star effects. With a 16 point filter, the many star lines may tend to overpower the rest of the image, so use it carefully. Generally, mid-range apertures or larger are sufficient to achieve a good star effect. Always test before critical situations.
This filter is specific to Cokin's "A" Series filter holder and rotates within the holder.