The Tiffen 6.6 x 6.6" 4-Point/2 mm Star Filter in glass creates multiple points of light, or "stars", radiating from a central light source. This can give the lighting in a scene a more sparkling and glamorous appearance. This effect is produced by a series of fine lines etched onto the flat optical surface of a clear filter.nnThe size and brightness of the star lines produced depend firstly on the size, shape and brightness of the light source.nnn- You have additional control through the choice of a particular spacing between the lines on the filter; These spacings are measured in millimetres and range from 1 mm to 4 mmn- A 1 mm spacing has twice as many lines as a 2 mm spacing; It will produce a brighter star for a given sourcen- Lines in one direction produce a two-pointed star, just a streak across the centre of the lightn- Tiffen offers symmetrical 4, 6 and 8-point star effects as well as additional asymmetric star patterns through their exclusive Hollywood FX series (North, Hyper, Vector and Hollywood star effects)n- With an 8-point filter, the many star lines can tend to dominate the rest of the image, so use it judiciouslyn- In general, medium or larger apertures are sufficient to achieve a good star effect; Always test before critical situationsnnnSpecificationsnn