After a clear protection filter, a polarizer is probably the first filter which any camera user should purchase. The principal use of the polarizer is to eliminate surface reflections, glare and hot spots from any light source entering the camera. This reflected light often shows up as a whitish glare which reduces the colour in the image. The polarizer is used for colour and contrast enhancement and removes reflections from substances such as water and glass. It can darken a blue sky and increases colour saturation.