This filter has no effect on the color balance but does reduce the amount of light reaching the film. It enables slow shutter speeds to be used, especially with fast films, to record movement in subjects such as waterfalls, clouds, cars, etc. It can be used to decrease depth of field by allowing wider apertures to be used to seperate subjects from backgrounds. Allows video cameras to record subjects such as snow or sand which would normally cause over-exposure. Filter factor: 1 stop.