These high quality glass filters manage the waveforms of light travelling to the camera from most reflective surfaces. Glare & reflected light can be altered by rotation of the polarising filter. The effect can be seen through the lens of reflex cameras as the filter is rotated. When used outside on sunny days, polarising filters have the effect of saturating colours & deepening blue skies. They can also be used in conjunction with other filters (although the polariser should always be placed in front of polyester filters to ensure itfunctions correctly). Polarising filters are available in two types, linear & circular. This is not referring to the physical shape of the filter, but to the way the filter changes the light waves thereby achieving the polarising effect. The type of polariser required (linear or circular) depends entirely on the type of camera the photographer is using. Modern reflex cameras with autofocus or complex metering systems, if used with apolariser, will only function co