Polarizing Filters are a great accessory for photographers. Some may argue that UV filters are a waste of money, and that colored filters are obsolete in the age of Photoshop, but polarized filters are still a fantastic tool particularly for landscape photography.
A polarizing filter will give you saturated blue skies and bright white clouds, verdant vegetation, and remove reflections from water.
Before you rush out and buy one for you or your loved one, here are some things you need to be aware of:
Buy the same diameter filter as the lens you’ll be using the filter on. To find out the lens diameter check on the back of the lens hood, or on the lens itself. It’s often written with a diameter symbol so it would look like this ⌀72 for a 72mm diameter lens.
“Wide” versions of polarizers are thinner (and more expensive) so they don’t result in vignetting of the image when placed on wide angle lenses.
Buy a circular not a linear polarizer. Linear polarizers can lead to autofocus problems with modern SLR cameras.
The quality of glass in the polarizer will have an effect on image quality and more significantly on price. The benefits of having a very expensive and sharp lens may be lost by using a cheap filter, but likewise you’re probably not going to notice the benefits of a 400 dollar polarizer compared to a cheaper one unless every other link in the image quality chain is solid.
I have a selection of polarizers I bought a decade ago, and although cameras and lenses have changed they are all still good to go. I always put them in my camera bag when I’m going on trips, a useful and sometime indispensable photographer’s tool.
I usually get my photographic gear from B&H Photo in the U.S. , Amazon.com , Amazon.co.uk , Amazon.co.jp or Yodobashi Camera but you should also be able to pick up polarizers from your local camera store.