The lee seven5 proglass 06 is a neutral density filter optimised for use with digital cameras but is equally useful for film the lee proglass 06 nd is designed for use with the lee seven5 filter holder not included and reduces the light reaching the sensor or film equally across the frame by 2 stops without affecting colour balance the reduction of light across enables the use of slower shutter speeds to record the movement of objects such as water clouds people cars etc nd filters