Cross Screen (CS) filter creates 4-beam flare on the light spots and is effective when shooting night illuminations, reflections on the water surface, light leaking through the leafs, photographs of jewelry and other scenes with tiny light sources.
Star filters are dramatic multi-point light flares or rays of light also know as a "star effect" to bright or strong point light sources in a scene. Star filters come in 3 different varieties: Cross Screen (CS), STAR-SIX and STAR-EIGHT, they have 4, 6 or 8 light beams respectively emanating from the light source.
HOYA star filters have lines etched in the surface of the high-quality optical glass to create the flare needed to create the star effect. Each of the filters, Cross Screen (CS), STAR-SIX and STAR-EIGHT have different patterns of lines etched in the glass to create the number of rays of light for the filter.