? PLEASE ENQUIRE AVAILABILITY BEFORE BOOKING ? Circular Polarising Filter 77mm (message for a list of compatible lenses) Deepens Blue Skies Cuts Down Reflections Improves Saturation Suitable for AF Suitable for Spot Meters A polarising filter is probably the most useful all-rounder after a protective UV filter. Polarising filters can be used to reduce reflections on glass or water and other non-metallic surfaces. Another major application is to increase colour saturation - particularly effective in landscape shots where the blue of the sky can be greatly enhanced. The filter itself is set in a rotating mount and you can vary the degree to which the image is affected by turning the front of the filter ring. It will reduce the amount of light reaching the film by a small amount (up to 2 stops), but a camera with TTL metering will compensate for this automatically.