The cokin p series p074 centre spot wide angle violet filter can allow the portrayal of an object to be diffused in violet coloured surroundings and has a clear spot in the centre which draws attention to the subject this filter is intended for use with a wide angle lenses the effect given by the filter is directly influenced by the f stop and the focal length this gives a softer transformation with wider apertures the selection of longer focal lengths determines the size of the clear c