* Correctional: compensates and/or modifies the exposure color
** Contrast and color correction: Try one of the Cokin Varicolor Filter Series
*** Yellow filter: increases yellow light and reduces the rest. Good for B&W photography.
*** Red filter: elimates fog and haze, recreates moon shots during the day, great for folliage shots.
*** Green filter: helps correct skin tone in portraits
*** Orange filter: increases the red and yellow contrasts. Good for sunsets.
*** Brown filter: creates a sepia-toned or aged photo with B&W film
** Color conversion filters: cooling and warming filters
** Flourescent filter: corrects unnatural light
** Neutral density filter: corrects the blinding effect of snow or sand
* Special Effects: used for creating soft focus
* Protective: instead of replacing your lens, simply replace the filter
** Protection filters keep your lens from becoming scratched, or from getting dirt, debris, and moisture into it.
* UV and haze filters (skylight) absorb UV rays to improve outdoor shots