In today's digital era, using a camera filter to manipulate or correct a camera's image might seem outdated. After all, given that you can apply color filters with a filter editor, remove a background with one click in Photoshop, or eliminate improbable camera shakes with stabilization software, it often feels like everything can be fixed in post.
However, camera filters remain an essential part of today's camera and lens ecosystem. This article will explain why and highlight the filters you should consider adding to your toolkit. You'll also find a bonus section on using various filters to recreate different looks in WeVideo’s editor.
A filmmaker using an ND filter. Image via Unsplash
Three essential filters for videos
1. Neutral density filters
First on our list, and perhaps the most important, is a neutral density (ND) filters. These filters help limit the amount of light passing through the lens and reaching the sensor.
When using a camera, we have three main settings to control light: aperture, ISO, and shutter speed. We often adjust these to let in more light when shooting in dark conditions. But what if there’s too much light?
You might ask, well, when is there going to be too much light? But actually, it's very easy to find yourself in a situation wishing there was some way to dim the sun. Suppose you want to film with a wide aperture to achieve shallow depth of field outside on a very bright day without adjusting some of the non-negotiable settings like framerate or ISO. In that case, your image will be completely overexposed. So, how do we fix this?
With a neutral density filter.
To summarize that video in a sentence: ND filters are like putting sunglasses over your lens.
Image via Unsplash
Their singular goal is to control the amount of light passing through the lens into the camera. Without them, you wouldn’t be able to film shallow depth-of-field shots in bright sunlight. They come in various strengths (measured in stops, the same measurement used for brightness in a lens) and are typically marked as ND2, ND4, ND8, and so on, with higher numbers indicating greater light reduction.
Of course, the downside is that you would need to buy multiple ND filters. Given that high-quality ND filters, those that keep the image free of color casts, can be expensive, you could quickly find yourself out of pocket.
If buying multiple filters doesn’t appeal to you, there’s an alternative: the variable ND filter. These filters consist of two stacked polarizing elements, allowing you to adjust the light reduction by rotating the front element.
This allows for an ND filter with multiple stops of light reduction, which is incredibly handy when working in environments with constantly changing light levels, such as filming in a meadow with clouds passing overhead. It significantly reduces the need to swap ND filters continuously and makes filming much easier.
However, it’s important to note that having two stacked filters can cause flaring and glare when facing strong light sources.
Image via Lewis McGregor
2. Circular polarizer filter
In the introduction, we discussed why using digital filters isn’t quite the same as applying a practical filter during filming on location. The circular polarizing filter might be the biggest example of why this is true.
When light comes from a direct source, like the sun, it oscillates in multiple directions, meaning it's unpolarized. However, when light reflects off surfaces such as water, metal, or glass, it oscillates in just one direction, which is parallel to the surface. It is these light rays that cause glare.
Image via Wikipedia
So, how does a circular polarizing filter help? Like an ND filter, it can be rotated. When you align the filter with the angle of the polarized light, it effectively removes the glare from the image.
As a result, details that are typically obscured by this light become visible, for example, details behind a car window’s reflection or beneath a pond’s surface. Additionally, it can enhance the saturation of colors on exterior objects illuminated by light. For instance, if you’re filming a beautiful row of bushes, but sunlight is washing out the colors, a polarizing filter can extract the glare from the image, leaving only the vivid green behind.
Image via Wikipedia
3. Diffusion filters
For a long time, filmmakers have sought to recreate the look of film. They’ve done this by adding grain, using digital LUTs to match film stock colors, and, more recently, by using diffusion filters.
Diffusion filters create a soft haze or glow around the brighter parts of an image, and depending on the filter’s strength, they can produce a dreamy, vintage look; which is primarily the normal use. However, when using a lower-strength diffusion filter, highlights transition smoothly from bright to overexposed areas, mimicking the way film handles harsh highlights.
Notice how this digital shot lacks a smooth transition to brighter areas. In digital images, bright highlights clip immediately into pure white, known as "clipping." A diffusion filter helps soften this transition, making the highlights more gradual and giving the image a more film-like and visually pleasing look.
After applying a diffusion filter, you can see that using a diffusion filter softens the harshness of the overexposed sky.
The science and engineering behind this effect are quite complex, but simply put, there are minuscule etchings all across the filter. When light hits the filter, it scatters in multiple directions, creating the characteristic haze effect.
This also highlights an important distinction: using filters is vastly different from applying a glow effect in post-production. When you use a filter, you’re altering the light before it reaches the sensor, which is fundamentally different from applying an effect afterward.
Not-so-useful filters in the digital era
These three filters are incredibly important for maximizing your composition potential. However, there are also a variety of filters on the market today that don’t serve as much purpose as they did 20 years ago. Let’s take a closer look at these.
UV filters
In the days of 35mm still film, keeping a UV filter permanently on your lens was common practice. This was because celluloid was susceptible to UV light, which could directly affect image quality. Too much of a blue tint or washed-out colors could occur, but a UV filter minimized the UV light reaching the film.
This photo would have benefited from a UV filter. Image via Unsplash
However, UV filters are no longer necessary in today's digital age. Modern cameras have protective coatings over the sensor and advanced image processing to handle UV light effectively.
Despite this, debates about their importance continue online. Today, the main reason people use UV filters is for lens protection. If you’ve invested $2,000 to $3,000 in a lens, many suggest that a $100 to $200 UV filter can help protect it from scratches and minor damage.
However, modern lenses, especially the expensive ones, are designed to withstand various challenging conditions. It takes considerable force to cause damage significant enough to break the glass or lens. Even in such cases, the front element serves as a protective barrier for the internal components and can be replaced if necessary.
Additionally, because adding another glass element to the front of the lens introduces potential image degradation, you would need a high-quality UV filter to avoid this. As a result, many now view the practice of placing UV filters on modern lenses and cameras as an antiquated idea.
If you wanted to protect your lens, the lens hood included with your lens would provide much better support.
Color filters
Color filters were once essential for adding different hues and tints to 35mm film. For example, they would attach a screw-on color filter to create a warmer look on a cold autumn day to achieve the desired effect; there was no Photoshop in 1975.
However, these are the least relevant of all the filters we've discussed today. With the power of modern post-production tools, there's no need to limit your camera’s potential by using color filters during shooting. In fact, you would be at a disadvantage as you would be locked into using that color, which isn’t ideal if you later change your mind.
Thankfully, the WeVideo editor comes with a wide variety of color filters that you can apply to your footage to receive similar effects as you would with a color filter over your lens. Let’s look at how you can achieve this.
Step 1: Select the Video Clip
First, select the video clip on the timeline you intend to apply a filter to.
Step 2: Access the Filters Panel
Once the clip is selected, go to the filters section (above the timeline). Here, you'll find a variety of filters to choose from, along with several designated categories for easy filtering (no pun intended).
Step 3: Previewing Filters
Hover over a filter to preview the effect on the clip in the preview window on the right-hand side. This handy feature allows you to assess how the filter will impact your footage before applying it.
Step 4: Applying Filters
You then can apply the filter to either the selected clip or all clips in the timeline. With your choice made, press apply, and the filter will then be applied to the selected video clip on your timeline.
How to attach filters
Now that we know what filters are, what they do, and a few additional types on the market, the next question is how we attach them to the lens.
Screw-on filters
Circular filters are the most common and budget-friendly option. They screw onto the front of your lens and can often be left on to avoid repeated removal. They take up minimal space in your gear bag.
Drawbacks:
- Circular filters depend on the lens's diameter. For example, a 77mm filter won't fit an 82mm lens.
- Purchasing filters for multiple lens sizes can become costly.
Image via Unsplash
To overcome this, you can use step-up or step-down rings to allow adaptation to different diameters. For example, a 77mm filter can be used across smaller lenses.
4 x 4 filters
These filters are an upgrade from circular filters and offer compatibility across various systems. They require a mount system since they lack lens threading.
Advantages:
- Excellent build quality and advanced coatings.
- Instant swapping and stacking of filters.
- Commonly used by photographers for graduated ND and color-based filters.
Image via Tiffen
For filmmaking, however, we need to look at 4.5x6.5 filters.
4 x 5.65 Filters - matte box
The gold standard for professional filmmaking, with individual filters costing $500 to several thousand dollars. These intricately engineered filters ensure no compromise in image quality for high-end cinema setups.
Usage:
- Slotted into a matte box, supported by 15mm or 19mm rods.
- A matte box includes a designated area for filter application.
Image via Lewis McGregor
This system quickly runs into thousands of dollars—before the camera is even turned on.
Final words
And there you have it: the core fundamentals of camera filters and the accessories required to use them. If your budget only allows for one filter and your camera doesn’t have a built-in neutral density filter, that should be your top priority. A variable ND filter is an excellent choice, as it can remain on the end of your lens indefinitely.
Check out our film school section for more tips and tricks on camera gear.