The Heliopan 39mm KR (1.5) Skylight Filter is a general use filter with a slight pink tint to help improve overall color accuracy and clarity. The light pink coloration helps to reduce the overall bluish cast of daylight and is especially effective when photographing landscapes and in shade. It is also useful as a general protective filter to leave on lenses at all times. Filters help to reduce dust and moisture from reaching your lens element and provide additional protection in case of drops or situations where scratching could occur. Also reduces bluish cast in snow scenes or of normal objects around noon time. It adds a pleasant warmth and soft color character with cameras whose sunlight white balance can be too cool. It absorbs UV Rays and serves as a protection filter. No exposure correction is necessary.