The camera lens filter is an optical accessory that is inserted in the optical path. It is a plastic or glass disk with metal or plastic frame and is attached to the lens. It is used to transform the raw images that are captured by the camera and carry them to a higher level. The use of filters saves the photographer from the time-consuming editing of pictures using the Photoshop. Editing pictures demands some technical know-how and is surely a challenge for beginners; too much of it distorts the natural look of an image.
Kinds of Camera Lens Filters
The Ultraviolet or Haze Filter is a clear lens that protects the lens from stains, dirt, dust, water, leaves, branches or any other things that you encounter during a photo shoot. So, this filter protects from tiny flying objects, haze particles and UV rays at the same time. UV light reduces the contrast, increases flare and adds a slight color shade on the image. It is advised to buy a multi-coated UV filter since it reduces much flare. The importance of a UV filter is being debated since it has some effects on the image quality, however, with a very expensive lens, protection is a priority. It is a lot cheaper to change a filter than a lens. Therefore, if the filter is already affecting the quality of the images negatively, then it can be replaced painlessly.
The Clear Protector Filter is purely for protection from lens damages caused by flying particles, objects or dirt. This filter also protects the lens from scratch or cross threading. It has no effect on the color of the image and should just be kept clean.
The Sky Filter is used to reduce blush tones and keep a natural skin tones. This kind of filter helps remove reflections from surrounding objects and can serve as a permanent lens protector.
The Polarizing Filter is used to remove highlights or reduce glare and reflection. Using half of the polarization level is enough to make the images look as natural as possible. If there is too much polarity, the sun will be too yellow or the sky will be overly blue. The contrast will be over the top making the images show some color distortions. This filter is very useful during sunny days or as long as there are a lot of reflections. It is less effective on cloudy or foggy days.
The linear and circular polarizing filters are considered to be the most essential of all filters for landscape photography. Linear polarizing filter is cheaper but it is not usable with through-the-lens (TTL) metering and AF cameras like most of the DSLRs.
The Graduated Neutral Density Filter is occasionally called the split filter. It has a slightly shadowy part and clarity on the other part. In case you will shoot a bright sky with a dark forest, you can position the filter in such a way that will lessen the brightness of the sunlight and maintain the shadows of the forest at the same time. In this way, the use of the filter will be unnoticeable in the photo and you can get rid of too much light without diminishing the darkness of the forest. There are different choices when buying the GND filter. It has the soft edge GND for any gradual change of colors from bright to dark. There is the hard edge GND for abrupt or sudden change of the intensity of light across the image like a highly visible partition between a dark island and a radiant sky.
And lastly, the radial blend that adds or eliminate light fall-off at the edge of the lens. The Neutral Density Filter is used to darken the images. It doesn't make any addition or distortion on the colors. It removes too much brightness and normally comes in 2 or 3 f-stops or one-fourth to one-eighth the amount of light. Darkening an image that is taken on a very bright day will help you see clearly the details of the surroundings. It can make moving subjects less visible, like a blurry motion picture. The Warming or Cooling Filter can change the white balance of light that reaches the sensor of the camera. This filter is actually correcting an unusual color cast or putting some warmth on an image. Most digital cameras these days have automatic adjustments for white balance, so, this filter is now becoming less popular.
Some Special Effects Filters
Sepia filters furnish a nostalgic effect to black and white photos or to ordinary colored images. Split Field filters make half of the picture a close-up image while the other half is just normal. Close-up filters magnify an image for a close-up photography. Rainbow Spot filters are for diffracting every tiny point of light to make a rainbow color. Intensifier filters make the colors intense and enhanced. Fog A & B filters create some romantic and mysterious effects of fog in any scenery.