Linear Versus Circular

• Contemporary cameras use beam splitters in their exposure and focus systems. Linear polarizing filters may affect the accuracy of these systems and are not recommend for use with these cameras unless you can bypass both autofocus and exposure systems. Circular polarizers, while not as dramatic in terms of reducing polarized light, are compatible with autofocus and exposure systems.
  
  

The "Toy Gun" Method

• When you're shooting in daylight, polarized light is greatest at an angle of 90 degrees off axis with the sun. You can "calculate" this by making your hand into a gun, pointing your index finger at the sun. Rotating your wrist back and forth will point to the part of the sky where the polarizing effect is the greatest.
  
  

Reflections

• Light reflecting off any non-metallic surface will be polarized to some extent. This light can be canceled by your filter. Putting this principle into practice, you may be able to reduce dramatically the images reflecting off a shop window, allowing you to shoot inside a building. Light reflecting off water can be filtered the same way, giving a more natural appearance to beach scenes.
  
  

Color Saturation

• When you're photographing plants and flowers, tiny droplets of water on the surfaces create a haze of polarized light. Adding a polarizing filter can remove the effect of the scattering haze, giving you deep, rich color effects. Similarly, under the right conditions, a polarizing lens can help cut through atmospheric haze in landscape shots.