The cokin warm 81ef colour filter is for use with a film camera using daylight colour film or a digital camera in automatic mode the warm 81ef is a strong colour correction filter that decreases the colour temperature from 3850k to 3200k the warm 81ef colour filter is for use in daylight to neutralise an excess of blue for example at midday in the summer the warm 81ef filter completes the cokin 81 filter range a b c d ef