- Like most filters and add-ons, polarizers are intended for cameras with removable lenses. Most point-and-shoot cameras and smartphone cameras are not compatible with external filters.
- There are two types of polarizing filters: linear and circular. Nearly all autofocus/auto-exposure cameras require circular polarizers.
- Camera-lens threads are standard, even on Nikons and Canons, so you need pay attention to only the diameter of your lens and buy the same-diameter filter (such as 52mm, 58mm, and 77mm).
- You get what you pay for. Inexpensive polarizers are built with aluminum rings, and these can bind with the threads of the lens. Also, better polarizers are multicoated, which prevents ghosting, lessens lens flare, and preserves contrast.
- Standard polarizing filters can introduce a slight blue hue to photos. Nautical photographer Billy Black (who has shot countless covers and spreads for Cruising World) says he prefers the warming type of polarizing filter because it removes a bit of the blue-green tones from images, giving his photos a more pleasant color balance.
- Reflections are not inherently bad. A circular polarizer allows you to select the amount of polarized light you wish to filter out, from none to all.
- Like polarized sunglasses, a polarizing filter reduces the amount of light that reaches your lens. In most cases, a camera will adjust the exposure to compensate. In other cases, the reduced light is not desirable.
- Once you begin using a polarizer, you'll be surprised by the reflections you didn't realize were there until they are gone. Even car tires are muted by reflected light and utterly changed when viewed through a polarizing filter.
- While post-processing software can do amazing things to a digital image, none can reproduce the effect of a polarizing filter.