Why polarizing filter

This all depends on whether a particular object is at an optimal angle to the sun, and whether this object is highly reflective. In general, more reflective objects will see a greater increase in saturation when using a polarizer. Clear sunny days are also much more heavily influenced by polarizers than overcast or rainy days. In the example to the right, the effect on the stone and foliage is subtle, but the sky becomes a noticeably darker blue.

Take care not to overdo this effect; unusually dark mid-day skies or overly vibrant foliage can easily make photos appear unrealistic. A polarizing filter can be an extremely powerful tool for removing reflections and isolating objects which are wet, underwater or behind a window. In the example below, a polarizer enables the photographer to select between subjects which are reflected from or are underneath the water's surface:.

In the above example, note how the polarizer was unable to remove reflections entirely although it did a pretty good job. This isn't ever possible, but fortunately polarizers are usually able to make reflections imperceptible unless they're relatively intense. Unfortunately the one exception is with metal surfaces — which often also happens to be the brightest and least desirable type of reflection.

A polarizer can also remove unwanted reflections when taking a photo out of a window or other transparent barrier. Move your mouse over the example to the left to see how a polarizer eliminates the window reflections. This can be a very useful tool when photographing objects within store windows, out a moving train or within a glass case, for example.

However, polarizers can also sometimes create an unrealistic-looking rainbow or ripple effect on windows which are uneven, have been tinted or are treated with coatings. A good example of this is something called "birefringement," which appears when taking a polarized photo through an airplane window:. Since polarizers reduce direct reflections, this often has the consequence of also reducing image contrast. This can make it easier to capture scenes with a broad dynamic range , such as trying to balance a bright sky with relatively unreflective land which can even make using a graduated neutral density filter or high dynamic range less important.

In the example below, the artistic intent was to literally highlight the curving road by portraying it in stark contrast to its surroundings. Using a polarizer actually detracted from this goal:. On the other hand, in most other situations a decrease in glare is desirable and generally creates a more pleasing photo.

For instance, in the above example the light doesn't appear as harsh and reflective on the rocks to the far right. In other situations polarizers can instead increase contrast. In the next example, the polarizer increased contrast by filtering the light reflecting off of the haze and sea spray. A polarising filter is perfect for enhancing tones in the Icelandic Highlands.

Photo by: ' Iurie Belegurschi'. You can either cut out the reflections altogether or use the polariser to create a mirrored effect. Reflection at Vestrahorn. Another situation in which you might consider using a polariser is to add definition to bright clouds. This technique can really make the clouds seem to pop out of the image.

You can also use a polarising filter to deepen the blueness of the sky and to minimise haze from fog or temperature inversion. This will result in a much clearer photo with enhanced details. Aside from these scenarios, you can use a polarising filter when you are trying to achieve a longer shutter speed, as these filters will naturally reduce light entering your lens by a few stops. This can help you to get that gorgeous dreamy effect on running water , like in waterfalls.

Although polarising filters can make your photos all the more brilliant, there are also times when they will be not very much help at all, or will make your photo look worse.

Adding an extra layer of glass to your lens increases the chances of lens flare. This is because wide-angle or fisheye lenses can cover an extraordinarily wide field of view. In general, it is also not a good idea to use a polarising filter when shooting images that you will stitch together later on to create panoramas. This means that you can end up with increased banding in the sky that is difficult to fix in post-processing. So to keep your sky clear and coloured evenly, remove the polariser when you are taking panoramas.

Another situation in which you might want to avoid using a polarising filter in Iceland is when the light has intense colour, such as during the Midnight Sun season or during sunrise or sunset. When the lighting is colourful or golden, removing the polariser can sometimes help you to take a better shot.

It allows the colour to be reflected off wet surfaces, meaning that the colour in the atmosphere will be enhanced and your photo will appear to be more dramatic.

Of course, if you want to highlight wet surfaces or reflections, then you will also probably want to remove your polarising filter. Polarising filters are not recommended if you want to highlight wet surfaces.

Photo by: 'Max Rive'. This includes during blue hour, when shooting at night, or when photographing the Aurora Borealis. If you want to reduce reflections in dim light or to maximise the clouds at sunset, then you will need to make adjustments by choosing a slower shutter speed, mounting your camera on a tripod, using a lower f-stop, or physically adding more light to the scene. The final scenario in which you might consider removing your polariser is when you are shooting rainbows at iconic locations, such as the waterfalls in Iceland.

Waterfalls are known for creating beautiful rainbows on sunny days, as they produce so much spray! If you are lucky, you may even catch a double rainbow. Although you can turn the polariser in a direction that enhances the colours of the rainbow, the filter can sometimes create a ripple or unrealistic effect, especially with a wide angle lens as we mentioned before.

Turned the other way, the polariser can minimise the visibility of the rainbow, making it seem dull and less vibrant. So to keep rainbows colourful and looking great in all of your photographs, experiment by having the polarising filter both on and off, as this is a situation in which the decision to use a polariser can swing either way.

Rainbows may either be enhanced or dulled by a polarising filter. This essential tool will ensure that you create dramatic photos that are vibrant and dynamic, enhancing your portfolio with truly great images.

About the author: Serena Dzenis is a landscape photographer based in Iceland. You can find more of her work on her website or by following her on Facebook and Instagram.

Experiment with using a polarising filter on a photography workshop in Iceland! Check out our 8 Day Summer Photography Workshop. Book Photo Tours. Explore Articles. Hold the rack so that the bars are horizontal. Only light that is wiggling horizontally will get through. Repeat with the bars oriented vertically. Use two cooling racks to show that if the polarizers are in opposite directions, no light will get through the pair.

Part 3: Exploration Hand out 2 pieces of polarizing filter to each student or small group. Sandwich the filters together, then hold them up and look through them.

Rotate one of the filters against the other while looking through them. Place different transparent objects between the two filters and look through. Extensions Someone wants to sell you a pair of expensive polarized sunglasses for a good price. What test could you improvise to know that they truly are polarized? Put your polarizing filters on either side of a clear plastic ruler or a plastic cup. Bend the ruler or the cup. Look at a black and white liquid crystal display LCD such as a digital watch through a polarizing filter.

Rotate the filter slowly 90 degrees. Related Resources Colour and Light How are rainbows made? What makes grass green and jeans blue? How do sunglasses work? In this series…. We believe that now, more than ever, the world needs people who care about science.