What is a polarizing filter? Polarizing filters

Today, photographers have a whole arsenal of tools at their disposal - modern digital cameras, lenses, additional equipment and, of course, filters. They are different and are used depending on the specific situation and task that the photographer sets for himself.

Deserves special attention polarizing filter for lens. Everyone has one good specialist. Install it on the lens on a sunny day to eliminate glare from non-metallic surfaces.

Colors become more saturated, the brightness of the sky blue is smoothed out. It is also possible to get rid of haze when photographing objects from a distance and from the glare of glass and water when photographing bodies of water. The position of the filter can be adjusted to obtain the desired shades in the photo that cannot be achieved through processing.

All manufacturers offer seemingly identical filters, but different prices. The cheapest ones are a glass filter in a thick frame.

More expensive models have thin frames, which eliminate vignetting when used on wide-angle equipment. Experts recommend not saving on this device and advise purchasing a high-quality product that will last a long time.

Using a polarizing filter allows you to block or transform polarized light that is reflected from shiny surfaces. To do this, a film is placed between two glass lenses. By turning the top ring of the filter, you can adjust the degree to which the polarization of light is blocked.

According to the effect they have on the image, filters are divided into:

• general purpose
• changing color,
• combined with other filters,
• enhancers of specific colors.
  General purpose polarizing filters are classified into two categories - linear and circular polarizing filters (also known as circular).

With the advent of digital, linear models practically disappeared from the market, however, the effect of their use is no worse than that of circular ones.

For digital cameras equipped with an autofocus function, the use of circular polarizing filters is recommended. It consists of two frames that rotate relative to each other to achieve the desired effect.

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• do not use on ultra-wide-angle lenses, as it will be difficult to achieve uniform polarization,
• the subject of shooting should be at right angles to the photographer, this will allow you to get the maximum effect; if the sun is behind or in front, the result of using the filter will be minimal,
• there will be no effect in diffuse lighting, for example, on a cloudy day,
• installing this type of filter on top of another can give a vignetting effect, reduce light transmission,
• Shooting through glass, such as a window, can give unpredictable results.

What to look for when buying - which polarizing filters are better

High-quality filters are not cheap. Thus, experts do not recommend spending money on devices costing less than one and a half thousand rubles.

Moreover, if you use different lenses, another problem arises - either buy a filter for each of them, or use an adapter. The easiest way out of the situation is to decide on the object you most frequently use and buy a device only for it.

To get started, select the right type devices - linear or circular. The second is required for digital cameras with autofocus.

It is important to pay attention to the materials from which the device is made. Look through it at the sky or your computer screen. Cheap devices will give interference in the form of a cloudy picture, an odd image. This will especially affect the quality of the photo when shooting with a camera with a high-quality matrix.

Ask the seller for several models and take identical shots to compare the results at maximum magnification.

For the good ones SLR cameras devices are selected according to diameter, it is indicated by the manufacturer on the packaging and on the device itself.

Based on manufacturers, filters can be roughly divided into the following categories:

• leaders: B+W Nano, Marumi Super DHG, Hoya Super HMC,
• average quality: B+W Pro, Marumi DHG, Hoya HMC,
• waterproof: B+W, Hoya HD, Marumi WPC CPL,
• standard - as a rule, all are of low quality.

Average quality devices with more affordable price can retain almost all the properties of favorites. In particular, it is worth noting the products of Marumi. With high quality, their price remains quite affordable. However, they do not offer innovative solutions, but simply make good filters for regular use.

But among the most best polarizing filters experts highlight the following:

1. Marumi DHG Super CPL. It has an ultra-thin frame, so it can be used even for 16mm lenses. It gets dirty quickly and is sometimes difficult to clean, but it confidently solves its problems. Production is located in Japan. It is worth noting that Japanese companies are confidently squeezing out German manufacturers, who not so long ago were the undisputed leaders.
2. Carl Zeiss T POL Filter. They are distinguished by thin frames, low weight, and lightweight construction. The cost is quite high, but it is justified by the excellent quality.
3. Hoya Super HMC. The main disadvantage is the lack of thread, which makes it impossible to simultaneous use with other types of filters.
4. B+W KSM Nano. The manufacturer uses an additional eighth layer without disturbing the color balance and light transmission. They are also equipped with a hydrophobic coating, which ensures that drops of moisture roll into balls and remove them from the glass. The brass frame reduces the risk of the device sticking to the lens.

Thus, if you are not a professional, you can opt for models in the mid-price category, which at an affordable price will provide the maximum high quality Images.

Companies producing DVRs are trying to attract the attention of buyers with various innovations - GPS and Wi-Fi module, G-sensor, and not so long ago the equipment was also equipped with polarizing filters. They are usually installed separately and are not included in the kit. Attached with a magnet or threaded connection.

Designed to eliminate glare and reflections from the windshield. The picture is clearer and more saturated. This is especially critical in bright sunny weather, while on a cloudy day and in the evening the result may be the opposite, so in such a situation it is better to remove the device.

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Purchase polarizing filter for Mia DVRs and other brands will improve image quality, which can be critical in the event of an emergency and further viewing of the recording with traffic police officers.

Agree, it will be a shame if the number of the person responsible for the accident turns out to be unreadable due to the glare of the sun or if it is not possible to see other details of what happened on the road.

Polarizing filters can increase color saturation and reduce reflections - and are the only filter that cannot be replicated in post-processing. This is an essential tool that any photographer should have in their bag. However, developing an intuition about how a polarizer can affect a photo often requires extensive experimentation. This article aims to speed up that process by demonstrating how and why polarizing filters can help (and sometimes hurt) in a variety of conditions.

General information

In the example above, a polarizing filter removes hard, direct glare on the surface of the water.

Polarizers are placed in front of the front lens of the lens, and their principle of operation is to filter direct reflections of sunlight at certain angles. This is useful because other light is often more diffuse and rich in color, but it also requires a longer exposure time (since some of the light is thrown back). The filtration angle is controlled by rotating the polarizing filter, and the strength of the effect depends on the position of the camera's line of sight relative to the sun.

Using polarizers: sun position and filter rotation

A polarizing filter is most effective when the camera's line of sight (shown below in red) is perpendicular to the sunlight:

The red discs indicate the directions of maximum filtration efficiency.
Green lines represent the ground/horizon.

A good way to think about this is to direct forefinger in the sun, while holding the large one at right angles to it. Any direction your thumb, as long as you rotate your hand while still pointing at the sun, will be the direction of maximum polarizer effect.

However, just because a filter has the greatest effect in these directions does not necessarily mean that it will have an effect in that direction. to look like as noticeable as possible. Rotating the filter will change the angle (relative to the sun) at which polarization appears maximum. The best way The way to feel a filter work is to rotate it while looking through the camera's viewfinder (or display), but you can also use the following explanation of the specifics of this process.

Note regarding filter rotation angle. In the limit, you can rotate the filter so that the direction of maximum polarization is perpendicular to the sunlight (as shown in the examples above). In this case, the polarization effect will be maximally expressed. If you then turn the filter slightly (say 10-20°), the polarization effect will become less pronounced. As the angle further decreases towards or away from the sun, the polarization effect will become less and less noticeable, and finally, when the filter is rotated a full 90°, it will no longer be noticeable. Subsequent rotation will lead to a new increase in the polarization effect and repeat the cycle.

Hurst Castle - San Simeon, California

Because the polarization effect depends on the angle, undesirable results may be obtained when using wide-angle lenses. Part of the image may be towards the sun, and part at right angles to it, in which case the polarization effect will be noticeable on one side of the image, but not on the other.

In the example on the left, the sun was almost at the horizon, causing the strip of sky directly overhead to be most affected by the polarizer (which made it darker), while the upper left and lower right corners (closer to the horizon) were largely unaffected. If a telephoto lens had been used to take the photo (with just one tower in the angle of view), the sky would have looked much smoother.

While wide-angle lenses are obviously not ideal, rotating the polarizing filter can sometimes make the effect more realistic. One way is to place the most pronounced polarization effect closer to the edge or corner of the image. In this case, the change in polarization will appear as a more natural gradient in the sky (such as occurs at dusk).

Color saturation

One of the first characteristics you'll probably notice about polarizers is how much they increase color saturation:

Columbia River Estuary State Park - Oregon, USA

When direct reflected light is filtered, the amount of diffuse light from the subject increases - resulting in a more colorful image. The green of the foliage will become brighter, the blue of the sky will become brighter, and the flowers will also become brighter.

However, color saturation does not always increase equally. All this depends on the optimal angle to the direction of the sun, as well as on the reflective ability of the object. In general, objects that reflect light more strongly will benefit more in color when using a polarizer. In addition, on a clear sunny day, the influence of polarizers is much more noticeable than on cloudy or rainy weather.

In the example on the right, the effect on the stone and foliage is barely noticeable, but the sky becomes noticeably darker. Take care not to exaggerate this effect; Typically dark midday skies or incredibly bright foliage can make photos look unrealistic.

Reflections, windows and transparency

A polarizing filter can be an extremely powerful tool for removing reflections and highlighting objects that are wet, underwater, or behind glass. In the following example, a polarizer allows the photographer to choose between reflections in the water and objects below the surface:

Note that the polarizer was not able to completely remove reflections (although it did a very good job). This is impossible to achieve in principle, but fortunately polarizers can make reflections that would otherwise be quite intense almost invisible. Unfortunately, the exception to the rule is metal surfaces, which also often create the brightest and least acceptable reflections.

A polarizer can also remove unwanted reflections when shooting through a window or other transparent barrier. Hover over the example on the left to see how the polarizer removes reflections in the window. This can be very useful when shooting from a store window, a moving train, or an object in a glass case, for example.

However, polarizers can also create an unnatural streak or ripple effect on uneven, painted or coated windows. A good example on the topic is the so-called “birefraction”, which appears when shooting with a polarizer from an airplane window:

Contrast and shine

Since polarizers suppress direct reflections, this often means a loss of image contrast as well. This can make it easier to shoot scenes with high dynamic range, such as when trying to balance a bright sky with a relatively dim ground (so a gradient ND filter or high dynamic range may not even be necessary).

However, reducing gloss and contrast is not always desirable. In the following example, the artistic intent was to (figuratively) highlight a curved road to make it stand out in contrast to the background. Using a polarizer actually prevented the goal from being achieved:

entrance to Canyon Island national park Sky - Utah, USA

On the other hand, in most situations, removing shine is desirable and usually creates a more pleasing photo. In this same example, the light on the rocks in the distance to the right doesn't look as hard.

In other situations, polarizers, on the contrary, can increase contrast. In the following example, a polarizer increased contrast by filtering out light reflected in haze and sea fumes. This effect looks most pronounced on the hills and cumulus clouds immediately behind them:

In general, using a polarizer on clouds and skies will almost always increase contrast, but if the subject is itself highly reflective, a polarizer will almost certainly reduce its contrast.

Flaws

While polarizing filters are obviously very useful, they do have their drawbacks:

• Because of them, the exposure may require 2-3 stops (4-8 times) more light than usual.
• These are some of the most expensive filters.
• They require a certain angle relative to the sun to achieve maximum effect.
• They can increase the composition selection time because they require rotation.
• They can be difficult to navigate through the camera's viewfinder.
• They can potentially reduce image quality (if the filter is not perfectly clean).
• They generally cannot be used for panoramic or wide-angle shots.

This panorama with a polarizer would look uneven, and the rainbow might simply disappear in some positions. Photo taken in Arches National Park, Utah.

Moreover, sometimes reflections in a photograph are needed. The two most prominent examples are sunsets and rainbows*; If you apply a polarizer to any of them, the color reflections may fade or disappear altogether.

*Note: Polarizers can sometimes enhance the color and contrast of a rainbow by shading background clouds, but only when rotated at the right angle. Additionally, full coverage of a rainbow typically requires a wide-angle lens, which can result in an uneven image of the entire scene or rainbow.

• Replacing the ND filter. A polarizing filter can sometimes be used when longer exposure times are needed. Since a polarizer can reduce the light transmitted by 2-3 stops (4-8 times), this is often sufficient for water/waterfall shots.
• Assessment using polarized glasses. Untinted polarized glasses can help assess how a photo will look. Just be sure to take them off before looking through your camera's viewfinder, as the double effect may prevent you from seeing anything.
• Thin filters on wide-angle lenses. A polarizer can sometimes create a noticeable darkening of the edges of the image (“vignetting”) when attached to a wide-angle lens. To avoid this, you will probably have to spend money on a more expensive “thin” option.
• Circular and linear polarizers. Circular polarizers were designed to ensure that the camera's metering and autofocus systems continue to function while the filter is in place. Linear polarizers are much cheaper, but cannot be used with most DSLR cameras (because they use TTL - through-the-lens metering - and phase detection autofocus).

The article also talks about this and other types of filters:

• Choice of filters: polarizing, protective, neutral and gradient.
  This review article about the different filters available to photographers.