Lens Filters

1. UV/Clear/Haze Filter

For: Any

Protects the front element of a lens from dust, dirt, moisture and potential scratches. High quality UV filters can be permanently mounted on lenses with a minimum impact on image quality.

2. Polarizing Filter

For: Any

Filters out polarized light, dramatically reducing reflections, enhancing colors and increasing contrast. Can be used for any type of photography. Polarizing filters are typically circular, allowing for easy control of the effect of polarization.

3. Neutral Density (ND) Filter

For: Landscape, Flash Photography

Reduces the amount of light entering the lens, thus decreasing camera shutter speed. Useful for situations where motion blur needs to be created (rivers, waterfalls, moving people) or large apertures must be used with flash to avoid overexposure.

4. Hard-Edge Graduated Neutral Density (GND) Filter

For: Landscape Photography

Hard-edge GND filters are primarily used in high contrast situations, where the sky is much brighter than the foreground and the horizon is flat. These filters are always rectangular (giving the ability to move them in all directions) and are typically used with filter holders.

5. Soft-Edge Graduated Neutral Density (GND) Filter

For: Landscape Photography

Soft-edge GND filters are also used in high contrast situations, but where the horizon is not necessarily flat. The soft edge allows for smoother transitions, making the use of a filter less evident. Soft-edge GND filters are also rectangular and are normally used with filter holders.

6. Reverse Graduated Neutral Density (GND) Filter

For: Landscape Photography

The reverse GND is a specialized filter used by landscape photographers when shooting against the sun while it is setting close to the horizon. While a regular GND filter gradually transitions from dark to clear towards the center, a reverse GND filter transitions from dark to less dark from the center to the edge.

7. Color/Warming/Cooling Filter

For: Any

Corrects colors, resulting in a change in camera white balance. Some color filters can subtract colors, blocking one type of color and allowing other colors through. These types of filters were popular for film. They are rarely used in digital photography, since their effects can be easily applied in post-processing.

8. Close-Up Filter

For: Macro Photography

Also known as “diopter”, a close-up filter allows a lens to focus closer on subjects. These filters are only used for macro photography.Special Effects FilterAnyThere are a few different types of special effects filters. Star filters make bright objects look star-like; softening/diffusion filters create a “dreamy” look used for portraits, multivision filters create multiple copies of a subject; infrared filters block infrared and pass visible light; bokeh filters have a certain shape cut in the middle of the filter that makes bokeh highlights have the same shape, etc.

Source:
http://photographylife.com/lens-filters-explained#ixzz2x3c1X7oK