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Photographers don’t talk about filters much and I catch myself doing the same. When someone asks me how I took a particular photo, I often forget to mention what photographic filters were involved (if any) and equally, people often get this idea in their head that all it takes to shoot great photos is an even better camera. Truth is that there are a lot of factors involved in taking amazing landscape photos. Yes it’s composition, shooting at the right time of day and owning a tripod, but filters are an important and rarely mentioned part of the process.
Since I enjoy landscape photography a whole lot, I rely on filters heavily when I go out into nature. For street photography, portraits or wildlife I do not use filters. Just like I wouldn’t put on sunglasses in a dark room, I won’t use filters when I don’t need them. So in this article, I will introduce you to the different types of photographic filters there are, when you should use them and how to buy the right filter for your lenses.
The basic types of photographic filters and how to use them
In old film cameras, UV Filters were used to block UV light and reduce the blue cast that would appear on photos taken on very sunny days. In modern cameras and lenses, these effects are insignificant and thus, the filter’s original function is superfluous. Today and because these filters are now basically just a clear piece of glass, UV Filters are simply used for protection. Some photographers leave them on their lenses permanently, while others don’t use them at all. It’s easier to clean dust and smears off an UV Filter and it’s definitely a lot cheaper to replace a filter due to a scratch than it is to buy a new lens. Chances are though, that anything that might seriously damage a UV Filter will also damage your lens and camera, but I suppose the survival chances of a lens during a fall for example, are a bit better if the front is protected with an additional piece of glass and it might give you some peace of mind.
Use UV Filters if you want to, but they are by no means necessary and make sure to take them off when shooting in low light situations. I personally don’t screw on my UV Filters very often. I mostly shoot during the golden and blue hours, when I have to leave them off to avoid light flares and ghost images due to stray light anyways. Afterwards, I mostly just forget to put them back on.
Polarizing Filters change how your camera captures glare and reflections. When shooting water for example, you might want to cut out reflections to give the water that crystal clear look. By cutting out the reflections and glare, the color of the water also looks a lot more vibrant. The color change is not only noticeable in water and applies throughout the picture: foliage can appear greener and the sky turns from a light, pale blue into a deeper, darker color. In short, if you want to get rid of any shiny areas, glare or reflections, use a Polarizing Filter.
Most people who use these filters go for the Circular Polarizing Filter, which allows you to adjust the strength of the filter by simply rotating it. Be aware that using a polarizing filter reduces the light that gets to your sensor by about 1-3 stops (depending on the strength you choose) – so be ready to adjust to a new exposure by either choosing a longer shutter speed, a larger aperture or a higher ISO setting. Accordingly, polarizers shouldn’t be used at night.
Neutral Density (ND) Filters
Have you ever wondered how landscape photographers capture moving clouds and silky smooth waterfalls or turn the roll of waves on a beach into a gentle mist in the middle of the day? Whenever you want to convey a sense of movement and you can’t get the shutter speed slow enough (aka it’s just not the right time of day yet or you actually want that bright daylight look), the Neutral Density Filters come in. These filters are basically a dark piece of glass that gets fixed onto the front of your lens to reduce the amount of light that reaches the camera’s sensor. Thanks to ND Filters, you won’t be bound to the conditions and they let you capture movement in whatever creative way you can come up with.
ND Filters can also come in very handy when shooting crowded tourist hot-spots. Simply screw on a powerful 10-stop filter and make moving people disappear into thin air with an ultra long exposure.
Now, the ND Filters I just talked about are an evenly dark piece of glass, but, there are a few other variations to consider as well.
Graduated ND Filters
Graduated ND Filters work just like the regular grad filters, with the difference being that only half of the filter is opaque and the other half is clear. Graduated ND Filters are used to darken a too bright spot of a scene that exceeds the dynamic range of your camera and to recover blown out highlights. Mostly, this applies to bringing back detail into a too bright sky and keep it from being overexposed.
Graduated ND Filters – soft or hard edge?
Hard Edge ND Filters
With these filters, the transition between opaque and clear is a hard, abrupt one. They are used on completely flat horizons where there is no object sticking into the sky and a definitive line between light and dark is needed. An example of this would be an ocean shot with a hard, clean line between water and sky. The transition line of the filter would then be placed right on the horizon.
Soft Edge ND Filters
Soft edge filters are a lot less noticeable than the hard edge filters, as the transition between dark and clear glass is more gradual. These filters are more natural and less limiting in their use and can be applied in a variety of settings, for example when you have foliage, mountains or buildings sticking out above the horizon.
Reverse Graduated ND Filters
This filter has one purpose and that is to help with sunrise and sunset photos when that glowing ball of fire is close to the horizon. They are a bit harder to visualize, but imagine it like this: If you’d divide the piece of glass into four equal parts, the top fourth would be darkened by one stop, the second one by three stops and the bottom two fourths would be clear with a soft transition between all parts. Reverse Graduated ND Filters are often a bit longer than average filters, in order for you to be able to position the darkest park right over the sun. Why not just use a regular graduated ND filter though? A simple graduated ND filter might not darken the sun enough, while leaving the top part of the sky too dark.
The different shapes of filters
There are many different filter systems available, the following two though are by far the most popular.
Circular Screw-On Filters
Circular screw on filters do just what their name implies and screw right on to the front of the lens. They are the easiest to use, as no holders or adapters are required, but they also match a specific lens diameter, meaning you will need one for every size lens you have or get a step up ring.
Square and Rectangular Filters
Square and rectangular filters come in a variety of sizes. They are more lightweight and a bit less expensive than screw on filters, but require an additional filter holder. With these filters, one filter fits all lenses, as long as you have the right adapter rings for the filter holder. Another benefit is that you are able to move the filter up and down to fit the scene exactly.
What you have to watch out for when buying filters
First, you will have to consider what strength and shape you prefer. This varies from person to person and depends on your own preference and creative goal. If you decide to get the square or rectangular filters though, I strongly recommend that you get a filter holder to go with them. Filters are pretty sensitive and scratch easily if you don’t treat them carefully. While it is possible to simply hold the filters in front of the lens with your hands, the movement of your hand and the contact between the front of the lens and the filter will result in scratches. Filter holders also keep your hands free, which is always a bonus.
Make sure to buy the filter and filter holder size that fits your lens
Filters come in a variety of shapes and sizes, make sure that whatever you buy is the correct size for your lens. Also make sure that the filter holder fits and doesn’t show up in the edges of your shots. If you don’t want to buy different sized filters for all your different sized lenses, consider step-up and step-down rings as an alternative. These rings are a bit lighter and cheaper than a filter and enable you to use a filter with a wider or smaller diameter than the lens you want to mount it on. Step down rings aren’t often used though, as they cause vignetting due to the filter being smaller than the lens and most people decide to simply buy the size that fits their biggest lens and step up if needed.
The difference between cheap and expensive photographic filters
This brings us to the incredibly wide price range of filters, starting at just a few dollars and going as high as several hundred bucks. The price of filters varies with the size of the filter, the quality of glass used and the number of coatings. More expensive filters will reduce vignetting, reflections and light flares. Some cheaper ND Filters will add a color cast to the image, which you’d then have to remove in post processing. If you’re like me and don’t have 200$ to spend on a single, top of the line filter, you will be well served with something in the mid range around 50-100$ as well. The difference isn’t as jarring and horrible as filter sellers want to make you believe and those filters will serve you well and yield good results if you treat them well. Be careful with the super cheap Chinese filters you can get off Ebay though, you do get what you pay for.
If I had to recommend two filters to start out with, it’s a 3-stop ND filter and a 3-stop graduated ND filter with a soft edge. These filters, which I myself use extensively, are a happy medium and work in a wide variety of situations.
Why do I need filters? Can’t I just add the same effect later on in post processing?
It’s always ideal to capture the perfect photo already in camera and don’t rely on post processing too much. I personally use Lightroom and Co. only for the finishing touches and try to get the lighting conditions right when I shoot the photos. You have to be aware that, even if you shoot RAW, fixing exposure, reflections, color and so on later on will also take away from the quality and introduce more noise into your photo. So you might be able to make some of the necessary adjustments in Lightroom, but the result will never be as good as when choosing the right exposure and using the correct filters.
If you absolutely don’t want to use filters, another solution is bracketing, also called exposure blending, which creates very similar results. This means that you take several images of the exact same scene (usually on a tripod) at different exposures. Later on in Photoshop you use layer masks to blend the proper exposures for sky and ground together into one single image. This is very accurate but involves a lot more work and creates some issues as well, such as ghosting. If you decide to use a ND Filter on the other hand, you only have to take one photo and don’t have all the extra work in post processing.