The Haida NanoPro Soft Star 2 in 1 filter combines a star filter and a soft-focus filter into one, creating multiple beams of light radiating outwards from point light sources in the image, while the soft-focus adds a halo around the light sources.
In general, mid-range or larger apertures are sufficient to achieve a good star effect, this effect being produced by a series of thin lines etched into the pure optical surface of a clear filter.
It creates a moody, dreamy glamorous atmosphere.