The cokin z pro 694 sunsoft resin filter is similar to the cokin soft warm 696 filter except that the sunsoft has a warmer tone as such it is also good for portraiture or any scenario where the photographer wishes to add additional warmth and diffusion to the image the z pro series is recommended for focal lengths of 20mm onwards in the 35mm format this filter is made of cr39 resin which is a reputable lightweight and unbreakable optical material also used for ophthalmic glasses used