Eco da i ja malo doprinesem ovoj temi. Iskopao sam nesto sa diska (imam pregrst toga o toliko stvari vezano uz fotografiju, da se vec pomalo gubim). Ne znam tocno od kuda je ovo preuzeto, ali stoji cinjenica da je vrlo korisno!

Filters

I use filters sparingly with color film and digital cameras. I mount UV filters (slightly yellowish) on my lenses for physical protection and to filter out UV light, which can fog film, especially at high altitudes (over 10,000 feet; 3,000 meters). There is some controversy about their use because they increase flare light slightly and moden films are less sensitive to UV than older films. I recommend multi-coated filters to minimize flare light. In many cases a lens shade (which you should always use if possible) provides adequate physical protection. Skylight filters (slightly pinkish) do essentially the same thing, but I use UV for consistency. Filters from reputable manufacturers do little to degrade sharpness. The only filter I use to alter the image is a polarizer. They can be used to darken the sky at angles around 90o from the sun. Sometimes, especially when there are high clouds early or late in the day, the effect can be dramatic. They can also be used to subdue distracting specular (shiny) reflections from non-metallic objects, especially water. (They can also be used to enhance reflections.) To minimize flare light I remove the UV filter when I mount a polarizer.

Split Neutral Density filters can be extremely helpful for capturing scenes with dark foregrounds and light skies, especially with digital cameras and slide films, which have a much narrower exposure range (5 or 6 f-stops) than negative films. To use them effectively you'll need a tripod and time-- they take a while to adjust. They come in one, two, and three f-stop gradations (densities of 0.3, 0.6, and 0.9) with sharp and soft boundaries. Links: Ray Barbee | Eastern Light.
Split ND filters can produce artificial results, especially when the boundary deviates from a straight line, for example, when part of the image protrudes into the sky. If you can capture all the information on film, contrast masking can be a more effective way of bringing the image into balance. If you have a digital camera and sturdy tripod, you can take double or multiple exposures and combine them. The Stack images transformation in Picture Window Pro 3.5 is particularly convenient for this purpose.

My favorite filters for Black & White are Yellow (darkens the sky so it looks subjectively correct), Orange (darkens the sky more; I liked it better), Red (darkens the sky deeply; rather unrealistic; favored by Ansel Adams for many of his most dramatic shots), and Green (my particular favorite because it lightens foliage; it also darkens skys about as much as yellow). Never use B&W filters on a digital camera. You get far better results applying a filter in software when you convert an image to B&W: Picture Window Pro's Monochrome transformation does a particularly fine job of allowing you to preview the effects of the filter.