With and Without: The Polarisation filter
In this blog, I would like to show what Polarisation filter does and why I use it. Every post in this category will consist of at least two images (and a few single images to make it more fun to read). One taken with a certain filter, and one without. I will add a description about what the actual filter does and why I choose to use it in this particular scene.
I hope it will inspire, give insight, and help to decide which filter to buy and use. In my opinion, using filters is the best way to get better results. If everything is right in-camera, you can spend more time in the field instead of behind a computer. In my opinion, photography is about being outside, creating beautiful images!
The polarization filter
This week, we will discuss the polarization filter. In last weeks video, you can see this filter in action. A filter capable of amazing things not possible in post-processing! That alone is why I think everybody should try this filter at least once to see its effect (after which you want to get one yourself for sure). This is one of the filters that I use so much! I love its effect and its power! When used correctly, it can add so much to your photo. And you can use it in so many different situations too. In fact, more often than not, this filter is on my camera and it is always in my bag where ever I go for photography. I even bring a spare one on longer photography trips and on my tours.
This filter can be bought as a screw-on filter but also for a filter system. I love to use the latter since this allows me to use the same filter on all of my lenses. Even on my ultra-wide angle lens. Therefore, I use the NiSi S5 filter system (150 mm) and the NiSi Landscape CPL.
How it works
In everyday life, unpolarized light from the sun (or when it is cloudy, from the sky) comes from different directions and is (partly) reflected or (partly) absorbed by objects around us. That is why we see those objects, their shape, their brightness, and color (or lack thereof when the light gets fully absorbed). Light that is reflected by an object becomes polarized. Because objects have different properties (color, texture, shape etc), light will be reflected in different directions. These properties will cause the reflected light to have a certain wavelength (color) and strength/brightness. When the texture is smooth and shiny, more light will be reflected (and polarized) in the same direction. That in turn causes a strong reflection or highlight to occur. Light reflected by color is much softer (to get a certain color, parts of the light are absorbed by the object) and therefore gets overpowered by the reflected highlight.
When we put a polarization filter in front of our lens, we will be able to block light with a certain polarization. This means that we will be able to block the glare, but let the light that reflects color enter the camera. For example, a polarizer rotated to pass only light in the direction perpendicular to the reflected light, will block light from all other directions. This effect applies to all reflections from shiny, non-metallic surfaces like, for example leaves, (wet)rocks, glass, skin, ice and even tree trunks. A polarization filter needs to be rotated to allow a certain direction of light to enter. This way, rainbows, reflections, and other polarized light will jump out or nearly disappear.
Therefor a polarization filter allows the natural color and detail of what lies beneath to be revealed. Fantastic for landscape photographers. But because the filter also removes reflections from glass, it is an amazing tool for architectural and cityscape photographers too. It will remove distracting reflections from windows, making it possible to see what is behind. It will remove glare from (wet) roads enhancing contrasts and it will add drama to the sky. This effect will greatly improve the drama and atmosphere in cityscapes, especially during blue hour and when it is wet.
The 90 degree angle rule
The strength of the polarization depends on its angle with the sun (or light source). The filter is at its strongest in a 90 degrees angle. When shooting straight into or away from the sun, its effect is at its weakest. In order to know where this maximum effect is you can form a pistol with your thumb and index finger, and point towards the sun. Keep pointing straight towards the sun and rotate your hand clockwise or counterclockwise. Your thumb will point towards the area with the maximum amount of polarization. To know where this spot lies is particularly important when shooting with an ultra-wide angle lens, or when taking panoramic images, but this we will discuss later.
The polarization filter is a popular filter, and for good reason. A filter that is capable of removing glare and reflections is a valuable tool! Therefore it is not hard to guess that one of the most well-known (and sought after) purposes for this filter is removing reflections from water. That is why most photographers love to use this filter around lakes, waterfalls and wet rocks! Imagine yourself standing at a lake, the water is crystal clear and the bottom is full of nicely colored pebbles. When you look close to your feet, you can see the bottom without any problem, but as soon as you look further than a few meters, the reflection starts blocking your vision and you won’t be able to see the bottom anymore. But even when you’re high above the surface and unable to see the bottom, this filter will have an incredible effect, as you can see on the next image.
If you look closely, you will be able to see a big difference. The most obvious is the glare on the sea. In the filtered image, this is mostly gone, revealing a deeper color and enhanced contrast. But if you look at the rocks and the color of the light, you can see that the colors are deepened and the reflections are removed too.
Plants and vegetation
Another purpose for which I love the polarization filter, is to remove reflections from plants and vegetation. Because most vegetation is covered in a protective waxy layer, its surface is often reflective. Therefore, color details get lost in highlighted parts. This also reduces the contrast, and with it, the impact the image has on the viewer. To illustrate this, I’ll use this image of a mushroom on a dead tree. In the unfiltered image, you can see that a lot of color, detail and contrast is lost. Instead you see a distinct white glare. This glare is visible on all parts that reflect light from above (I was in a forest). In post-processing, I won’t be able to get rid of this because the information that lies underneath is lost. After I had attached the polarization filter, the effect is easy to see. It is a completely different image. The ugly and somewhat distracting glare is mostly gone and the colors are much more prominent. This draws all the attention to the nicely colored mushroom.
A certain type of photography for which the polarization filter is really awesome, is woodland photography. This is where this filter really shines! The reason for this can be explained with the 90 degrees angle rule I mentioned earlier. When you are in a forest, the light mainly comes from above. This means that when you apply the 90 degrees angle rule, the maximum polarization effect lies in an horizontal plane. In other words, the maximum effect lies all around you. Combine this with a forest in its full autumn colors and the effect is simply mind blowing!
Looking at this image, the effect of the polarization filter is immediately visible when looking at the road. The glare is gone, making it much darker. But when looking at the leaves on the ground, the leaves that form the canopy of the forest, and the tree trunks, you notice that the glare is gone too. The colors are much deeper and warmer, and the overall contrast of the image is much stronger. In my opinion, the glare causes a disturbance and makes the image less pleasing to look at. With the glare gone, the disturbance is gone. Which makes for a stronger and better image.
How to use this filter?
As we can see, the polarization filter is a strong and valuable tool for landscape photographers, but how and when do we use such a filter? Well, with the 90 degrees rule in mind, you’ll know where the maximum effect lies, but even when shooting sunset straight into the sun, I find that it has a useful effect because the sky itself often causes a lot of glare on the foreground/subject. After attaching the filter to the lens, I look for the maximum effect by rotating the filter, it can be helpful to zoom in on certain parts of the photo using live-view. When I’ve reached this maximum, I’ll look for possible errors introduced by this, for instance caused by over polarization. If that is the case, I reduce the filters effect until I am satisfied. This of course is subject to taste, so if you like dark blue skies, go ahead and do so (but make sure to prevent errors discussed in the next section)! If I observe no effect, or the effect is not satisfying, I remove the filter.
When using a polarization filter, there are a few things to keep in mind! First of all, if the filter has no effect, don’t leave it on the lens. Remove it! Some photographers think that if it doesn’t work, it doesn’t do any harm either. But that is wrong. It will reduce the amount of light with 1 to 3 stops (depending on the brand and quality) and it if the glass has a low quality, it will reduce the sharpness of the image.
One thing that you shouldn’t forget is when you take a photograph in landscape orientation, and you change the camera to portrait orientation, you have to readjust the filter accordingly. It sounds logic, but trust me it is easily forgotten when you are excited. It happened to me too. Always double check and don’t rush!
When shooting panoramic images while using a polarization filter, make sure to correct for the angle with the sun. This means that you have to readjust the polarizer every time you move the camera for the next image. Check every image and make sure that you won’t introduce a dark spot exactly where the polarization is at its strongest. Have a look at the following image to see what I mean:
The same problem occurs when using an ultra wide angle lens. Try to avoid a lot of sky in your image or reduce the effect. Keep this and the 90 degrees rule in mind when composing your image and make sure to check the result. This can be done by using live-view. The last thing you should try to avoid, but this is a matter of taste, is over-polarizing an image. When doing so, the sky becomes really dark blue, so much that it starts to look unnatural. This effect can be really nice in black and white alpine scenes but often an image will start to look fake.
Thanks a lot for reading
That’s it for this week’s article! I hope you learned something from it and if you have any questions, tips or advice feel free to let me know! If you enjoyed reading it, please feel free to share on social media! And, if you like my photography, please follow me on Instagram @harmenpiekema If you want to read more about filters, check out this post.
Was this helpful to you? Are you still confused? Leave me a comment down below!