Polarising Filter Principle
What Is a Polarising Filter?
A polarising filter is a photographic tool that is used to reduce reflections and glare, and to increase colour saturation.
It works by selectively transmitting light of a specific polarisation to eliminate unwanted reflections from surfaces such as water, glass or metal.
How a Polarising Filter Works
A polarising filter works on the principle of polarising light, i.e. selectively transmitting light waves of a specific orientation. When light reflects off a surface, it becomes polarised in a specific direction.
A polarising filter blocks these polarised waves, allowing only those that are not polarised to pass through. This makes it possible to reduce reflections and increase contrast and colour saturation in photography.
Basic Filter Types
Polarising filters are divided into two main types
- Circular filters
- Linear filters
Circular filters are more popular because they are compatible with modern equipped autofocus and light metering systems. Line filters, although less popular, can be used on older analogue cameras.
Circular Filters
Circular filters (CPL) are the most commonly used polarising filters in photography. They consist of two layers:
- The first polarises the light
- The second converts it back into circular light.
As a result, CPL filters do not interfere with the autofocus and light metering systems of modern cameras. An example of a popular CPL filter is the B+W Circular Polarizer, which is prized for its high quality and durability.
Linear Filters
Linear filters are less common in digital photography, but are still used in some situations.
They consist of a single polarising layer that blocks light waves of a specific orientation. These filters can interfere with systems and light metering and are therefore less commonly used in modern cameras.
Nevertheless, they can be useful in analogue photography and in some specialised applications such as technical or scientific photography.
Differences Between UV and Polarizing Filters
UV filters and polarising filters have different functions and are used for different purposes.
A UV filter, as the name suggests, protects against ultraviolet radiation, which can cause haze and contrast reduction in photographs.
A polarising filter, on the other hand, is used to reduce reflections and glare and increase colour saturation.
AUV filter is often used to protect the lens, while a polarising filter is mainly used to improve image quality in certain lighting conditions.
Using a Polarising Filter in Landscape Photography
One of the most important uses of a polarising filter in landscape photography is to increase the colour intensity of the sky and vegetation. This filter allows the colours to be saturated, making the sky bluer and the vegetation to gain deeper shades of green.
Reducing Reflections From Water Surfaces and Glass
The polarising filter is extremely effective in reducing reflections from the surface of water and glass. This allows lakes, rivers or ponds to be photographed without unwanted reflections, capturing the depth and clarity of water.
Influence of the Shooting Angle on the Polarisation Effect
The polarisation effect is most apparent when the photo is taken at 90 degrees to the direction of sunlight. In practice, this means that the best results can be obtained when the sun is to the sides, rather than directly in front or behind the photographer.
Practical Techniques for Using a Polarising Filter Outdoors
Using a polarising filter outdoors requires certain skills and techniques. First of all, it is worth remembering to rotate the filter regularly to find the optimum angle of polarisation.
It is also worth paying attention to the lighting conditions – if the sun is strong, a polarising filter can significantly improve the quality of your photos.
Polarising Filter in Street and Portrait Photography
Reduction of Unwanted Reflections and Glare on the Skin
A polarising filter is useful for portrait photography, especially outdoors, where natural light can cause unwanted reflections and glare on the skin. By using a filter, these reflections can be effectively reduced, allowing for a more natural looking skin.
When outdoors, always carry a polarising filter with you to control glare and reflections on the skin.
How to Avoid Excessive Polarisation in Portraiture
Although a polarising filter is useful, excessive polarisation can lead to unnatural effects, especially in portrait photography. To avoid this, the angle and intensity of polarisation should be chosen carefully. It is important not to over-rotate the filter, as this can result in over-saturated colours and a loss of natural look.
Polarisation Control in Urban Conditions
In street photography, polarisation control is key to achieving the desired effects. In cities where glass and metal predominate, a polarising filter can significantly reduce reflections and glare, allowing for clearer and more aesthetically pleasing images.
Aesthetic Effects and Creative Applications
The polarising filter also offers many creative applications for street and portrait photography. It can be used to create dramatic effects by increasing contrast and colour saturation, adding depth and clarity to photographs.
An example is a photograph taken during golden hour, where the polarising filter allows for more intense sky colours and more dramatic shadows, adding an artistic touch to the photo.
Polarising Filter in Product Photography
Removing Blips From Reflective Packaging Surfaces
In product photography, one of the main challenges is eliminating blips and reflections that can distort the look. A polarising filter is extremely helpful here, as it helps to reduce reflections from surfaces such as plastic, glass or metal.
An example is cosmetics photography, where reflections from glossy packaging can distract from the product itself. By using a polarising filter, it is possible to achieve clean, professional photographs that better reflect the actual appearance of the product.
The Benefits of Using a Polarising Filter in Advertising Photography
In advertising photography, image quality is crucial to attracting the attention of potential customers. A polarising filter can significantly improve the quality of images by eliminating reflections and increasing colour saturation.
An example of this can be seen in an advertising campaign for luxury watches, where the use of a polarising filter helps to eliminate reflections from metal envelopes and glass dials, making the images more attractive and crisp.
The polarising filter is also an invaluable tool in the arsenal of the commercial photographer.
Practical Examples and Photo Shoots Using a Polarising Filter
A practical example of the use of a polarising filter can be a jewellery photo shoot. Photographing shiny surfaces, such as gold or silver, often involves the problem of unwanted reflections that can distort the appearance of the product.
With the use of a polarising filter, it is possible to obtain clean, clear photos that better reflect the details and quality of the jewellery.
Achieving Polarisation in Post-Production
Colour and Contrast Intensification in Adobe Lightroom and Photoshop
One of the main uses of a polarising filter in post-production is to intensify colour and contrast. In programs such as Adobe Lightroom and Photoshop, this can be achieved using tools such as the saturation and contrast slider.
In Lightroom, the ‘Vibrance’ slider allows you to subtly increase colour saturation without over-saturating colours, which is particularly useful in landscape and urban photography.
In Photoshop, on the other hand, the ‘Curves’ tool allows precise contrast control for more dramatic effects.
Removing Reflections and Blips With Retouching Tools
Removing reflections and blips in post-production is possible with the advanced retouching tools available in Adobe Photoshop. The “Clone Stamp” tool and the “Healing Brush” allow you to precisely remove unwanted reflections from surfaces such as glass or metal.
Retouching a product photo, where reflections from packaging can be effectively removed, allows for a more professional look. It is also worth using layers and masks to control the editing process and keep the photo looking natural.
It is worth using layer masks to precisely control the process of removing reflections and blips.
Masking and Selective Editing Techniques
Masking and selective editing techniques are extremely useful for achieving polarised effects in post-production.
In Adobe Photoshop, the ‘Layer Mask’ tool allows you to control precisely which parts of the image are edited. This allows you to selectively increase colour saturation or remove reflections only in selected areas of the image. Masking techniques are key to achieving professional results.
Plug-In Overview
Numerous plug-ins and tools are available on the market to help you achieve polarising effects in post-production.
NIK Collection
An example is the Nik Collection plug-in from DxO, which offers advanced colour and contrast editing tools, allowing you to achieve effects similar to those of a polarising filter.
Luminar
Another example is the ‘Luminar’ plug-in from Skylum, which offers features such as AI Enhance to automatically improve colour and contrast.
These plug-ins are extremely helpful for photographers who want to improve the quality of their images quickly and efficiently.
In conclusion, understanding the various effects that a polarizing filter can produce in different contexts is key to mastering its use in photography.
Knowing how to use a polarizing filter can significantly reduce glare and enhance saturation, resulting in images with a professional and clean aesthetic.
For those venturing into polarising filter photography, it’s essential to note that the position of the sun and the angle at which you shoot can greatly influence the effectiveness of the filter. A polarizing filter does more than just darken the sky; it allows for the control of light in a way that digital post-production cannot always replicate.
Whether capturing the serenity of landscape scenes or the intricate details in street and product photography, the polarizing filter is an indispensable tool for photographers aiming to elevate the quality of their imagery.
