Why You Need A Polarising Filter In Your Kit Bag

 

It fits in front of the camera lens and has a rotating front ring. As you turn this the polarising effect can be viewed through the camera viewfinder or on the LCD.

 

We don't always see a mirror-like reflection, it's often glare - seen as the light bouncing off the surface. A polariser will reduce this. So on foliage the lush green is often reduced by reflected light to a pale shade. Add a polariser and the glare is reduced and the bright colourful nature of the foliage returns. It's the same with animal fur and skin - the sheen will be reduced and the natural colour will be enhanced.

We won't go into the technical details of how it works, but rest assured if there's a reflection on water, on glass or on other flat surfaces, excluding bare metal, the polariser will help to reduce that reflection and let the natural surface show through.

The polariser is also used to deepen blue skies. If the sky is blue you can make it rich blue with the polariser rotated to its strongest position. This is what the travel company photographers do to ensure their location pictures are rich and inviting in their brochures. 
 

You don't have to have the polariser on the lens to see if it's going to be effective. Hold it up to your eye and rotate the ring. If it makes a difference to your scene, screw it on. In bright conditions we'd suggest you leave the polariser on all the time. If you want reflections to appear, such as a harbour scene where you want the mirror effect in still water, turn the filter to its least effective position. If you want to see the fish below the surface, rotate it round to the strongest position.

When shooting to prevent reflections, it's best if you are at an angle of around 35 degrees to the reflective surface.

Take care when using a polarising filter on a lens wider than 28mm, not only can you get vignetting where the lens is so wide it's caught the edges of the filter in the corners of the frame, but the effect can look false as only a proportion of the sky will be deeply polarised.