The Beginner’s Guide to Camera Filters: What you need, what you don’t and why

Camera filters are an easy way to quickly improve your photography -- but the wrong type can quickly ruin a photography (and a budget). Here's what beginners need to know about camera filters from type to name brand.
By Hillary Grigonis, Last updated on: 8/1/2016

Camera filters were a thing long before Instagram — they prevented film glitches, helped enhance contrast and more. But do camera filters really have any draw in digital when filters are as easy as Instagram and as elaborate as Lightroom presets?

Absolutely. While there are a number of filters that can be replicated digitally with the same results, there are a handful of filters that will create in-camera results that you can’t mimic digitally. The right filters can create dramatic skies, widen the possibilities within a single photograph, add special effects and even protect your lens from scratches. The wrong filters? They’ll get you wasting money on things that take less than a minute to achieve on a computer and could even wreck an otherwise great image.

When it comes to camera filters, there’s a lot to learn, but there’s also a lot to gain. Here’s all the camera filter basics along with what ones you need, what ones you don’t and why.

Camera filters

A screw-in circular polarizing filer

What are camera filters?

A camera captures light — a camera filter prevents a certain type of light from entering the image or otherwise alters the light that comes in through the lens. By filtering out different colors of light (i.e. wavelengths) or even different types (like infrared), a camera filter can make a dramatic impact on the image, without any editing.

Camera filters come in types based on the type of light they filter out, but they also come in two different formats within those categories. Circular filters screw into the threads at the end of the lens, while plate filters are held in place over the lens by a large holder that fits over the lens.

Circular filters are often cheaper and they also take up less space in your camera bag. Square plate filters tend to me more expensive, but they can also be layered without creating a vignette in the photo. Sometimes, the type that’s best depends on what kind of filter you are buying. Circular polarizing filters, as the name suggests, are always the screw-in type. Graduated filters that apply the effect to only a portion of the image are more popular in the plate version because you can adjust the position of the filter inside the plate to apply the effect to only the portion you want.

Whether you decide to pick up a circular or plate filter, you’ll need to choose the size that fits your lens. The lens’ thread size is written in mm on the inside of the lens cap. Square plate filters often have multiple adapters to adjust the holder to fit on multiple lenses. Circular filters are fit to that lens — but you can buy the filter for the largest lens that you have, then buy a step up ring that adapts the filter to your other lenses. (It’s important not to buy a smaller filter with a wider adapter — it won’t cover the whole image). Step up rings allow a single filter to be used with every lens in your bag.

Camera filters

A plate-style graduated neutral density filter

Types of Camera Filters

Besides the shape and size, filters are categorized by the type of light that they filter out, or the effect that they have on the photograph. The most popular filters for digital photographers are circular polarizing filters, neutral density filters, graduated neutral density filters and some special effect filters. Some photographers also choose to add a filter that doesn’t have any effect on the image quality to prevent the front of the lens from scratches. Here are the best filters for digital photography that either can’t be replicated in editing or are pretty tough to do so.

Circular polarizing filter

Of all the camera filers I own, the circular polarizer is my favorite (and cannot be imitated in Photoshop). Polarizing filters control reflected light. I first picked one up so that I could enhance reflections on glass and water. By twisting the front of the filter, you can control the reflections, whether you want to enhance them or eliminate them.

But polarizing filters have one even bigger use — enhancing the sky. If you remember from science class, the sky appears blue because of reflected light (essentially, anyways). Since this filter controls reflected light photographers can actually use it to control the color of the sky. Twisting the filter will deepen or lighten the sky’s color. Along with enhancing the sky, polarizers tend to do well at adding contrast to green landscapes.

Reflections are all about angles — and adjusting the angle of your camera while using a polarizing filter will also play a role in just how intense the effect is. You’ll notice you have the most control using your polarizing filter shooting at a 90 degree angle from the sun. If the sun is behind you, the effect will be much smaller.

Circular polarizing filters literally give photographers the ability to control the sky (cue evil laugh from your favorite power-addicted super villain) — but they are some precautions to using them. Used with a lens wider than 24mm, the effect won’t be universal across the image — you’ll notice the sky is darker in some areas than others. Whether that’s a cool effect or something to be avoided is up to you, but it’s certainly something worth noting. Polarizing filters also cut out a significant amount of light — you won’t want to leave them on your camera for low light shots.

Neutral Density Filter

Think of neutral density filters as a nice pair of shades for your camera. By blocking some of the light, they allow photographers to use slower shutter speeds or wider apertures than the conditions would normally allow. Often, neutral density filters are used to shoot long exposures during the day. ND filters can also be used to shoot with a wide f/1.8 aperture in bright sunlight without overexposing the image, especially when using a fill flash. Most cameras can’t go past a 1/250 shutter speed when using flash, so in bright enough conditions, you have to use a narrow aperture — or you can limit some of that light with an ND filter.

Unlike most filters, neutral density filters don’t block out a certain type of light — they reduce light as a whole on all wavelengths. They’re not designed for creating a certain effect, but to give the photographer more freedom to use slow shutter speeds or fast apertures. Just like wearing a pair of sunglasses reduces the brightness of what you’re seeing but doesn’t create crazy colors, to an untrained eye, non-photographers won’t be able to pick up on the fact that a filter was used at all.

These filters come in different densities to block out a little light or a lot of light. Which one you need depends largely on the shooting conditions. A .6 ND will reduce light by two stops, or by about four times what’s coming into a filter-free lens. A .9 ND reduces light by eight times, or three stops. Both are considered moderate filters for small changes — like using a wide aperture or a shutter speed slow enough to blur a river or waterfall in daylight. For creating more extreme blur in the middle of the day, stronger filters like a 3.0 ND (10 stop reduction), 4.0 ND (13 stops) and 6.0 ND (20 stops) are used.

Neutral density filters are also often sold in sets, so photographers can pull out the intensity they need for the shooting conditions.

Neutral density filters can be circular or square plate filters. The plate filter type is often preferred for NDs because it makes it possible to stack multiple filters and intensify the effect for extreme long exposures. Some circular filters will stack, but they’ll create a vignette, or a dark edge on the photograph.

Graduated Neutral Density Filter

Graduated Neutral Density (GND) or grads are neutral density filters, but they only cover a portion of the image. By applying the darkening effect over just some of the image, you can darken a section of the image that’s overexposed. Most commonly, grads are used to prevent overexposing the sky, leaving details like the clouds and color intact even on a bright day.

Along with coming in different densities just like regular NDs, grads have two more types: hard and soft. The hard grad has a more abrupt transition from light to dark, while the soft has, you guessed it, a softer transition. Hard grads tend to be used when the horizon is perfectly straight, though it’s also a bit of a personal preference.

While graduated neutral density filters do come in the circular type, they’re best avoided. The circular grads transition from light to dark in the center, which means you have to put the horizon in the center to darken the sky. That’s not a big issue, but it limits your composition options. The plate filters, on the other hand, can be pulled in and out of the filter holder to sit on the horizon almost anywhere in the image, so your composition isn’t limited by the filter.

Grads are very powerful tools for landscape photography. While they may come in handy for a few other genres, the cost is more justified for landscape photographers.

Special effect filters

Polarizers, NDs and grads are the most common filters because they are very useful in a number of different scenarios and aren’t limited to a single effect. But, there are a number of special effect filters that some photographers use. While they are limited to a specific look, these special effect filters still find a home inside many digital photographer’s bags.

Infrared (IR) filters are a more affordable alternative to buying an IR camera. IR isn’t visible light, so IR images are much different than the photos were are accustomed to seeing — for example, with an IR filter green grass turns white and you can even see right through a pair of sunglasses. If you like the look of IR images, an IR filter is a fun tool to experiment with. The downside? By filtering out all light but IR, there’s not much light left so every shot you take with this filter will be a long exposure (which means you’ll need a tripod).

Star filters take points of light and turn them into, you guessed it, stars. A grid pattern over the glass creates stars by splitting the light into points. Turning the filter allows you to change the direction those points are heading in. Star filters aren’t a necessity, but they can be fun to use, especially for night photography. You can generate this effect in Photoshop, but it’s a bit time intensive and these filters often aren’t very expensive.

Do you need a UV filter?

UV filters are no longer necessary on digital cameras — but many photographers still use them. Why? UV filters (or at least good UV filters) don’t impact the image quality, but having a filter could potentially protect the front of your lens from scratches. Whether or not UV filters really protect the lens is highly debated. Some companies also make lenses designed specifically as a protective filter. While a filter isn’t going to help if you drop the lens, theoretically, they should prevent scratching. It’s much easier to replace an inexpensive UV filter than it is to replace an entire lens.

What filters can be replicated digitally?

While polarizers, NDs and grads can’t be replicated digitally, there are a number of different filters that can be easily recreated with software and with similar, if not exact, results. That doesn’t mean using a filter is wrong, after all it is always better to get it right in camera. But it doesn’t make much sense to spend money on filters and weigh down your camera bag when applying them digitally takes almost just as much time as digging a filter out.

Colored filters were initially used with black and white film to create more contrast, since many colors convert to a similar shade of gray. Lightroom now comes with one-click presets that recreate these effects. The orange filter, for example, hides skin blemsihes while the yellow filter enhances the sky slightly.

White balance filters were once used to correct white balance issues, but since you can do that in-camera (or in post processing) they aren’t very useful in digital photography.

Soft filters are a type of special effect filter that softens the entire image or just the edges. I have one in my camera bag — and I never use it. Soft effects can be recreated digitally, and but you can’t sharpen an image that you used a soft filter on if you change you mind later.

Budget vs. brand name filters

Filters come in almost as many price points as they do categories. So what’s the difference between a $20 filter and a $200 filter? Is it worth spending more on a filter?

Budget filters get the job done, but they may (or may not) lower the quality of the photograph. One of the biggest issues that pop up with cheap filters is ghosting and flare. Well-made filters will have coatings to prevent these issues while cheaper filters will not.

In general, the more expensive, brand name filters will prevent ghosting and flare while also avoiding the loss of sharpness. Some cheap filters will also alter the colors in an image. Off-brand filters are also poorly built and can be harder to use.

That doesn’t mean hobbyist photographers need to spend hundreds on filters though. Start by looking for filters from a reputable camera store — avoid third party sellers and especially avoid any product listings that don’t even list the brand of the filter. There are filter brands that don’t have the price of a Schneider or B+W but are still going to give your images a nice boost — if you’re on a budget, look into options from Tiffen or Hoya, and make sure to read the user reviews. There may be a difference in quality, but when you choose a budget brand that still has a good reputation, that difference is much smaller, especially for hobbyists.

Remember, another way to save money on filters is to buy one that fits your largest lens, then purchase adapter rings to accommodate the other sizes. That’s an easy way to get one filter to stretch across all your lenses.

Filters are simple and often essential tools. While a number of different filters are no longer necessary with digital cameras, polarizers, NDs and grads can’t be replicated in Photoshop. Filters are one of the easiest ways to improve your photography without spending thousands on new gear — and some images are even impossible without them.

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