Lens Filters. What, Why, and When to Use Them

What are lens filters?

Wikipedia defines it as a layer of glass, gelatine, or other material used to modify the spectrum of the incidental light. Lens filters can be used for controlling the rendering of color or for diminishing the intensity of light.

lens-filters

Camera filters are transparent or translucent optical elements that alter the properties of light entering the camera lens for the purpose of improving the image being recorded. Filters can affect contrast, sharpness, highlight flare, color, and light intensity, either individually, or in various combinations. They can also create a variety of “special effects.” It is important to recognize that, even though there are many possibly confusing variations and applications, all filters behave a reasonably predictable way when their properties are understood and experienced. Most of these properties related similarly to filter use in both film and video imaging. The following will explain the basic optical characteristics of Tiffen and certain other types of camera filters, as well as their applications. It is a foundation upon which to build by experience. Textual data cannot fully inform. There is always something new out there.

Filtration will affect the light levels that the lens will receive. Filters that have certain characteristics can have variable strengths are grades. It’s also good to note that your focal length can affect the visible strength of a filter.

HERE ARE SOME OF THE MOST COMMON LENS FILTERS

Polarizing Filter

Polarizers allow color and contrast enhancement, as well as reflection control, using optical principles different from any other filter types.

Polarizer filters are like putting a pair of sunglasses in front of the lens. It removes reflections from glass, shiny surfaces and water, and it enables you to film what is behind a window or under the water, rather than a surface full of reflections.
Polarizing filters also give you greater contrast and more saturated colors.
They can make the sky darker, which definitely helps when you are shooting environments and landscapes.

UV Filter

A UV filter looks like just a clear piece of glass, but it improves color reproduction and eliminates blur caused by ultraviolet radiation. Ultraviolet light is invisible to the eye but can be picked up by the camera sensor.

There are many locations and scenarios where ultraviolet light can affect your image such as:

Hazy weather
Mountainous Regions
Coastal Areas
Areas with very clear air.

UV filters don’t need any additional light to compensate for exposure. One common use for UV filters is to be permanently mounted on the lens for protection.When you attach this filter on top of the lens glass, it is the actual filter that is exposed to any dust and scratches. It is much cheaper to replace a filter if you scratch or damage it, than to replace the entire lens. UV filters are also referred to as Haze filters and are designed to cut through the effects of atmospheric haze, moisture and other forms of airborne pollutants, each of which contributes to image degradation.) Remember that UV filters are additional pieces of glass you are putting on your lens. Don’t get cheap filters and put them on expensive lenses because those filters will definitely impact the image quality.

ND (Neutral Density) Filter

A neutral density filter absorbs light of all wavelengths. Think of an ND filter like a dimmer you can put on your lens to control the amount of light entering that lens. Neutral Density filters allow you to shoot with slower shutter speeds or large apertures, even in very bright situations.

ND filters can be used for many different reasons, such as:

ND filters are great for balancing exposure on day exteriors with lots of sun.
It can also be used for taking down the intensity of light in situations like if you are filming in the snow.

ND filters are available in different strengths, depending on how much light you want to block out. Variable ND filters are great because one filter can be used to get a variety of filter strengths.

Check out the video below from Tiffen:

Things To Consider (Recap)

UV / Haze and Skylight filters protect the surface of your lens against scratches, dust, moisture and fingerprints, which in the long term can harm the lens coatings. UV / Haze and Skylight filters also minimize atmospheric haze, which results in better overall image quality.
The difference between an inexpensive filter and a more expensive one has to do with the quality of the glass (the costlier filter most likely contains optically purer and thinner glass), the quality of the anti-reflective and color coatings and retaining ring (better filters have brass rings instead of aluminum).
Polarizing filters reduce or eliminate distracting reflections from the surface of glass, water and other polished surfaces, darken skies, make clouds pop from their surroundings and saturate color by reducing stray ambient glare.
Polarizing filters are also available combined with warming filters, enhancing filters and diffusion filters. Weather-resistant Kaeseman Polarizers are also available for use in extreme, damp climates.
Neutral density (ND) filters block varying degrees of light from striking the imaging sensor (or film) in order to shoot at wider apertures under bright lighting conditions. It blurs moving objects in the frame regardless of ambient light levels and allow for better exposure control when shooting video or film.
ND and Color Graduated filters darken or tint the top or bottom (or left and right) portion of the frame while leaving the opposite side untouched. They are used for equalizing exposures of scenes containing extreme lighting variables on opposing sides of the frame.
Filters can come as a conventional circular glass screw filter. Lens filters are also available as square and rectangular filters made out of polyester, gelatin and resin. These filters, some of which are optically purer than glass filters holders like a rods and a matte-box system.
If you plan on using one filter on several lenses, you should purchase a slim or thin version to better ensure it won’t vignette the corners of the frame when used on a wide-angle lens.

Here is great video that shows you every LEE Filter compared:

The Lee Diffusions App is really cool iPhone app for also seeing how filters can affect your image.

https://itunes.apple.com/us/app/lee-diffusion-comparator/id1050979715?mt=8

What filters do you use and why? Let me know. Join the Capturing Light Facebook community: https://www.facebook.com/groups/capturinglightcommunity/.