Lee Filters LEE85 ND Reverse Grads comes in three densities: 0.6 - 2 stops, 0.9 - 3 stops and 1.2 - 4 stops. These reverse grads are specifically designed to provide complete control when shooting as the sun rising and then as it sets. The density is strongest in the centre of the filter (the opposite to standard ND filters) which prevents the sky from burning out and allows the entire frame to correct exposed. Trying to achieve a correctly exposed image that highlights all the scene's detail is extremely difficult without a reverse grad. Reverse grads are aimed at those who are photographing horizons, where the sky and your foreground need a balance in exposure for dramatic early morning and evening scenes.