To help you better understand the different types of photo filters on the market, we’ve broken down the five most common filters. In each section, we explain the purpose of each filter to help you better understand whether or not you should invest in one for your photography bag.
Polarizer (linear and circular)
One could easily make the argument that of all the filters on this list, a polarizing (also called polarizer) filter the most important. Why? Because its effect on the image is one that can’t be replicated in post-production.
The purpose of a polarizing filter is to reduce the amount of reflected light that hits your camera’s sensor. As a result, the skies in your image will appear a darker shade of blue, glares on water will be more subdued, and the overall contrast of the scene will be reduced.
There are two types of polarizing filters: linear and circular. Circular is by and large the most popular, due to the fact linear polarizing filters interfere with the autofocus and autoexposure functions of most modern DSLRs. That said, if you don’t mind manually hitting focus and exposure, you could save a bit of money by going with a linear polarizing filter.
The intensity of a polarizing filter can change depending on two variables: how it’s positioned when in front of the lens, and the location of the sun. Rotating a polarizing filter when mounted on the front of the lens will change how much reflected light is let through the lens, a useful feature that lets you dial in just how much you want to reduce the contrast of the image. Likewise, the sun’s location in the sky will have an impact on how dramatic the polarizing effect is. The effect is most intense when your lens is facing perpendicular to the sun. That means the effect will be most noticeable when the sun is directly overhead.
Neutral density (ND)
Unlike polarizing filters, which selectively reduce reflected light in a scene, the purpose of a neutral-density (ND) filter is to minimize all of the light entering the lens. The benefit of this is you can use much slower shutter speeds than would otherwise be possible, even with the lowest ISO and maximum aperture settings.
This effect is most used in landscape photography, when the goal is to smooth out a moving part of an image. Take for example the photo below. To make the water appear smooth and to give the representation of motion, an ND filter was used to achieve a much slower shutter speed than would have otherwise been possible without blocking a large amount of light.
Another use of ND filters is when you desire a shallow depth of field in bright light. For example, let’s say you have an f/1.2 lens on hand while shooting outside at noon on a sunny day. Odds are, without an ND filter, you won’t be able to shoot at f/1.2, even if your ISO is all the way down at 100. To remedy this problem, slap on an ND filter designed to block out a few stops of light and you’ll be free to shoot at whatever aperture you please.
Although all ND filters reduce the light entering the camera lens, not all do so at the same level. Neutral-density filters come in different strengths, usually represented by the number of “stops” it reduces the incoming light — that is, each sequential number reduces the amount of light by half. The levels can vary from as little as one stop, all the way up to 15 stops as seen in Lee Filter’s Super Stopper.
Graduated neutral density (GND)
Neutral-density filters are great for when you want to reduce all of the light entering your camera. But what if you only want part of the scene to be affected? Enter graduated neutral-density (GND) filters.
As the name suggests, GND filters only block out the light on part of the frame. The purpose of this is to reduce the amount of light entering the camera in areas of the photo where it would otherwise be considered too bright.
Take for example the photos below. The image on the left, captured without a filter, loses a great deal of detail in the sky. The image on the right, captured with a Lee Filter’s 0.9-stop GND filter, retains the tones in the clouds and sky.
As dramatic of a difference as GND filters can make in-camera, their use isn’t mandatory. Thanks to the increased amount of image information in RAW photo formats and the ability to stitch multiple images together in post-production via high dynamic range (HDR) photography, you can easily replicate the effect of GND filters in Photoshop or Lightroom with digital filters.
But for those who prefer to get things done in-camera or have particular use cases, such as having a moving subject in the frame, you can’t beat a quality GND filter.
UV (haze)
In the days of film, ultraviolet (UV) filters served the purpose of removing ultraviolet light — often seen in the form of haze — from an image. Now though, UV filters are little more than a means to protect the front element of your lens. The reason for this is because digital sensors are far less sensitive to ultraviolet light than analog film.
Despite the lack of visual benefit from a UV filter, many photographers still use them as a means of protection. After all, the last thing you want is a scratch on the front element of your new, expensive lens. But the benefits may very well be overshadowed by the disadvantages. UV filters, especially cheaper ones, can cause unwanted lens flares and ghosting issues in images.
Ultimately, it comes down to personal preference whether or not you use a UV filter. If you’re hoping to keep your lens in the best shape, a UV filter might be in your interest. If you don’t want the risk of image degradation due to a UV filter, feel free to go without protection.
Warming/Cooling
Even more so than UV filters, warming and cooling filters have gone much the wayside since the advent of digital photography. In the days of film photography, warming and cooling filters were used to alter the white balance of an image by changing the warmth or coolness before it was forever imprinted on the negative.
Now with digital cameras, especially those capable of capturing RAW images, the need to get white balance in-camera is far less important. Not only is the auto white balance feature of most cameras extremely accurate, but even the most simple of editing programs are capable of warming up or cooling down the tones in an image.
It’s safe to say you can absolutely go without ever owning a warming or cooling filter. That said, if you do want to try them out, you can find both warming and cooling filters at B&H Photo or other good camera sellers.
