Last week on the podcast, I mentioned circular polarizers a couple of times. After that episode published, I had conversations with a few listeners asking about filters in general and how they can improve your photography, and I figured there would be more people with these questions. Hence, today’s episode, all about filters.
Now, the filters I’m talking about are NOT the ones you put on a picture in an editing application or on a social media platform. Those are digital filters, and they are vastly different than what we are talking about. We are discussing real-life filters. These types of filters are super crucial for anyone looking to up their photography game. They can allow you to drag out time and create silky smooth water or get rid of tourists. They can balance out an overly bright sky versus the ground, add (or remove) a colour cast, reduce glare and reflections, and add a punch of colour and vibrancy.
Pretty much any type of photographer can benefit from using filters. But those who will benefit the most are those who shoot landscapes, travel-scapes, and adventure portraiture.
How are Filters Mounted?
Before we get into talking about the filters themselves, let’s talk about how filters are mounted to a lens. There are two common ways filters are mounted: directly onto the filter threads at the front, or on an adapter that is screwed onto the filter threads. There is a third type, called drop-in filters that go near the back of a lens, but those are on highly specialized pieces of glass or with specific adapters and aren’t nearly as common as the other two.
The first type of filter, the ones that screw directly onto the filter threads, are circular filters. These are typically very portable, don’t add heft and size to your lens set up and are easily used while exploring locations. The downside is that they typically can’t be stacked with other types of filters. You usually get one, and that is it.
The second type of filter goes on an adapter that is screwed into the lens threads. These are typically square or rectangular filters. The advantage of these is that they are stackable. You can put two or more together (depending on your adapter) to create different effects and strengths of impact. This is huge for crafting specific images. The downside is that these filters add a lot of bulk to your lens and take up a lot of space in your bag. They aren’t as easy to explore with.
So those are the two common types of filters. Circular thread mount filters and square/rectangular filters. Now, on to the filters themselves and what they do.
Filters come in various styles and needs, but we will be discussing only the most important ones to keep it simple. They are neutral density filters, variable neutral density filters, graduated neutral density and circular polarizers.
Neutral Density Filters (ND Filters)
These filters’ job is to block light coming into your camera by adding a dark piece of glass onto the lens; how dark will depend on what you need. This allows you to decrease your shutter speed and drag out how time and light enters your camera. Or to reduce your aperture, allowing you to craft creamier backgrounds in very bright light.
They are talked about in terms of stops of light they block. You can get them in strengths to block everything from a half stop of light up to 10 stops or more. I’ve seen them go up to 22 stops of light, which is a tremendous amount of light to block. The most common strengths that people use are 3, 6, and 10 stop NDs.
ND filters come in both rectangular/square and circular varieties.
The primary time you will be using these in travel photography is to help stretch out the exposure length. This will allow you to blur the movement of crowds, smooth out the clouds, or show a waterfall flow. You will typically need to be mounted on a tripod to get the most out of these filters.
They can also be helpful when you are doing portraits with off-camera lighting. But many of us won’t be doing that, so I’m not going to go down that road here.
Variable Neutral Density (VND) filter.
In its simplest terms, a variable ND provides you with multiple ND filters in one circular mount for the front of your lens. To use them, you mount the filter onto the lens and then turn it to select how many stops of light you want to block out. You can get variable NDs in various strengths; you need to find one that suits you. The strength of this is that you only need one ND filter in your bag, and you can change its strength depending on the situation. Unfortunately, these filters can suffer from various problems, including a big black X showing up in the middle of the image when the strength is set too high. They can also cause some other image quality issues like colour casting and vignetting. So they work great for quick, on the run fixes, but won’t provide you with the image quality of a straight neutral density filter.
Graduated Neutral Density filter
Next up is the graduated neutral density filters. These come in both square and circular forms. They are a filter that has a dark portion on half the filter, and it slowly transitions into a transparent filter on the other half. These are useful for more balanced exposures between the sky and the ground because you can darken the sky while leaving the land untouched. The circular ones work well, but don’t leave you much room compositionally for where the horizon will be in the image. The more useful version of these filters is the rectangular one because you can choose exactly how much of the sky or the ground is covered with the filter. These also come in a variety of strengths.
The primary time you will be using these is to create more balanced and blended exposures without needing to shoot in HDR.
Finally, we come to circular polarizers. I mentioned these last week, but we will get into them a bit more now. As the name suggests, circular polarizers are a circular filter. To use one, you mount it on your camera and rotate it until you see the desired effect in your image. Polarizers do several things, including reducing glare and reflections off water, glass, and other shiny objects. They also cause the sky to be a deeper blue and to let colours pop more. Polarizers are one of the filters you cannot fake in post, and because of this are one of the most common filters photographers use today.
They can significantly enhance your work, simply because you can remove distracting glare from water and because they allow you to shoot through glass and get a cleaner image. Circular polarizers are one of the simplest ways that you can improve your photography.
Most circular polarizers are attached directly to the filter threads, meaning you can’t easily use them with other filters.
Some companies offer circular polarizers that can be dropped into their adapters to be used with square and rectangular NDs and graduated NDs. If you want this, you will need to make sure the company making your filters offers this.
What to Look for When you Buy Filters
- Material they are made from
- Get high quality glass filters
- No colour casting
- Mounting options
- Ensure they will fit your lens, or get step up rings for them
One last note here about filters. Don’t go buying cheap ones. You can get filters made of plastic or cheap glass, but don’t do this! Filters made from inferior materials will cause colour cast, vignetting, and other issues in your images that are near impossible to fix in post. Filters can be expensive, but the cost of getting good ones is well worth it. You are spending good money on expensive lenses, don’t go and put a cheap $20 filter in front of all that beautiful glass. Get filters that are just as high quality as the lenses you use.