Filters are usually a small glass adapter that screws into the threaded ring at the end of your camera lens. They are most commonly used on DSLR cameras. There are a variety of filters that can be used to better the quality of your photos without editing or just to add some artistic effects. Here is a breakdown of the most common filters you will find.
The most common use of a Skylight/UV filter is to simply protect the front lens element from damage; it is much cheaper to replace a ten dollar filter than a six hundred dollar lens.
The UV filter is also used to lessen the negative effects that can be caused by a range of environments. You would use this filter when you are shooting in an area with heavy atmospheric haze or other pollutants to the air like smog. These can degrade your image quality.
This could also benefit you when taking pictures at higher altitudes around large bodies of water or snowy conditions. Those elements all act as a magnifier for ultra violet light.
When using this filter, you may need to adjust your exposure to compensate for the effect this will have on the lighting in your photo. There are varying strengths of the UV filter for the amount of ultra violet filtration they provide.
When photographing in the outdoors, the polarizing filter can help reduce glare or reflections from shiny surfaces like glass or water. It is also known to help saturate colors; it is especially helpful in making the sky appear bluer.
Circular and Linear are the two different types of polarizing filters available. If you can adjust the angle of the camera to the light, while still achieving the desired exposure, a linear polarizer should work fine.
On the other hand, if you cannot adjust the angle of the camera to the light, you will need a Circular polarizer. On a Circular polarizer, you may adjust the level of effect by twisting the filter to varying levels as it spins on a secondary ring.
Circular polarizers are the most common and are the most flexible. When using this filter you will lose light in the filtering process and will need to adjust your exposure accordingly.
This filter is used to reduce the amount of light entering the lens. This will allow you to achieve different effects, like blurring motion or a shallow depth of field. In very bright situations, they help to prevent an image that has too much light, which then turns out overexposed due to your shutter speed and aperture combinations.
This filter will affect the intensity of all of the colors equally and not affect the hue of the photograph. Much like the polarizing filter, you spin this filter on a secondary ring as to adjust the intensity of the filter.
These are exactly as they sound. There is a color graduation starting at one end of the filter and reducing in effect toward the other side. These can be used to intensify a portion of the image while not affecting the other. You could use these filters to make a sunset or sunrise sky to look warmer or cooler without affecting the land portion of the image. There a variety of colors you can purchase for different effects.
Black and White Contrast Filters
This is a filter that will reduce excess ultra violet and blue light to help correct the black and white image. It can also produce higher levels of contrast between different colored objects in a picture that doesn’t have “color”. As an example, two totally different colors could look like the same shade in a black and white photo if they reflect the same amount of light.
Color Compensating Filters
Some of these filters will require an adapter ring and a filter holder that will use the threads; like most other filters, at the end of your existing lens. These filter holders will sometimes hold a clear, but colored, square. These are normally used to apply a solid shade of color to the entire image.
You could find one for almost any array of color you desire. A filter of a certain shade could be used to correct color in a photo or for artistic purposes. Using these may occasionally require adjusting your exposure settings according to the strength and shade of color you use.
Image Softening Filters
These filters are sometimes also referred to as a Diffusion Filters. The purpose of this filter is to create a softer image. It can be used to soften imperfections in someone’s skin when doing portrait photography, or smooth out a landscape shot. It could also create a glowing effect to highlighted areas of the photo or to reduce the contrast. They are not to be confused as a filter that creates a blur effect, as they have a minimal effect on the sharpness of the image.