Lens Light Pollution Filters: Universal Or Unique?

Light pollution filters are a great way to enhance your astrophotography and low-light photography, especially if you live in a big city. These filters are designed to block out the yellow and orange light emitted by sodium vapour lamps, the main source of light pollution. They can be attached to the front of your lens, slid into a filter holder, or clipped inside the camera.

There are a variety of light pollution filters available on the market, ranging from premium to budget-friendly options. Some popular choices include the Irix Edge Light Pollution Filter, Hoya Starscape Light Pollution Cut Filter, and the K&F Concept Natural Night Light Pollution Filter.

It's important to note that light pollution filters may not work as effectively with the newer LED street lights, which emit a whiter light. Additionally, they may introduce a colour cast to your images, but this can usually be corrected in post-processing.

Before purchasing a light pollution filter, consider your specific needs and the level of light pollution in your area. If you live in an area with high light pollution (Bortle 7+), you may want to explore other options like narrowband filters or travelling to a darker location.

Light pollution filters can be screwed onto the front of a lens, put into a filter holder, or clipped inside the camera

Light pollution filters can be attached to your camera setup in several ways. The most common method is to screw the filter onto the front of your lens, like any other filter. This is a simple and effective way to reduce light pollution in your images. Another option is to use a filter holder, which allows you to slide the filter into place. This method provides more flexibility, as you can easily switch between different filters. Additionally, some cameras allow you to clip the filter inside the camera body, close to the sensor. This placement ensures that the filter is as close as possible to the light source, maximizing its effectiveness.

Screwing the filter onto the front of your lens is a convenient and straightforward method. Most light pollution filters are designed to be screwed onto the lens, making them widely accessible. This method ensures that the filter is securely attached and won't move during your photography session. It is worth noting that you need to select the correct filter size that matches your lens' filter thread to avoid compatibility issues.

Using a filter holder offers the advantage of versatility. If you plan to use multiple filters or switch between different types of filters, a filter holder is a convenient option. It allows you to quickly change filters without having to screw and unscrew them from your lens. This method is particularly useful if you want to experiment with different types of filters or adapt to changing lighting conditions.

Clipping the filter inside your camera, close to the sensor, is another effective approach. This placement ensures that the filter is positioned between the light source and the sensor, maximizing its ability to block light pollution. Optolong, for example, offers clip-in filters for select Canon, Nikon, and Sony camera bodies. However, it is crucial to ensure that you purchase the correct size for your specific camera model to avoid compatibility issues.

While each method has its advantages, the effectiveness of light pollution filters also depends on the lighting conditions and the level of light pollution. In areas with high levels of light pollution, you may find that even with a filter, capturing the Milky Way or the Orion Nebula from the center of a big city remains challenging. Additionally, the type of light pollution can impact the filter's effectiveness. Traditional sodium vapor lamps emit a yellow/orange light, which most light pollution filters are designed to block. However, with the increasing use of LED lights, which emit a whiter light, the effectiveness of filters may vary.

Light pollution filters are designed to block out the wavelengths of light emitted by sodium vapour lamps

Light pollution filters are very popular in the astro community. They allow you to take amazing astro images, even in light-polluted areas. However, not all light pollution is from sodium vapour lamps. White light from LEDs is becoming more and more common. While these new LED lights may reduce the ugly yellow/orange glow from cities, they still produce light pollution.

There are various types of light pollution filters to choose from. Some can be screwed to the front of your lens, slid into a filter holder, or clipped inside the camera itself. There are also filters that require a telescope to be installed.

A good quality light pollution filter can be relatively affordable, but some of the higher-end models can be more expensive.

Filters can be made of didymium, a mixture of the rare-earth metals praseodymium and neodymium

Light pollution filters are designed to suppress the emissions generated by artificial lighting, such as street lamps, which can ruin astrophotography images. Filters can be made of didymium, a mixture of the rare-earth metals praseodymium and neodymium. This type of filter can significantly reduce the transmission of light from sodium vapour and mercury vapour lamps, which emit yellow and orange light, ruining night-time images.

Didymium filters are multi-coated and can be used with various lens sizes. They are designed to block the wavelengths of light that are the main cause of light pollution, from 575nm to 600nm. This helps the camera to capture the correct colour of the night sky, enhancing the contrast between the sky and the ground. The filter does not add any colour to the images but stops the wavelengths of the polluting lights, restoring the true and beautiful colours of the landscape.

Didymium light pollution filters are available in various sizes and can be purchased with adapters to fit different lens sizes. They are a useful tool for astrophotographers and night-time photographers who want to capture clear, accurate images of the night sky without the yellow/green colour cast caused by artificial lighting.

Filters can be used in urban areas to capture more natural-looking images

For example, the Hoya Starscape Light Pollution Cut Filter reduces yellowish and greenish colour casts caused by street lights. The K&F Concept Natural Night Light Pollution Filter helps stop yellow and orange wavelengths of light from entering the lens, making it adept at reducing the impact of conventional street lighting. The NiSi Circular Natural Night Filter is another example of a light pollution filter that fits on the DJI Phantom 4 Pro and the Mavic Pro, which are ideal for shooting nighttime cityscapes.

The type of light pollution filter you need depends on the type of camera you use for astrophotography. For instance, a stock DSLR camera will be much less effective when paired with a multi-narrowband filter. Broadband filters are used to capture more natural-looking images of objects in the night sky, while multi-narrowband filters ignore most wavelengths of light in the visible spectrum.

Filters can be used during the daytime to enhance the overall contrast of an image

Light pollution filters are designed to reduce light pollution in your images by blocking out specific colours, usually those with wavelengths between 570nm and 620nm on the visible spectrum, which corresponds to orange and red colours. They are particularly useful for astrophotography and night-time photography in urban areas, where light pollution can obscure the details of the night sky and stars.

Light pollution filters can be used during the daytime to enhance the overall contrast of an image and increase saturation in red and magenta tones. This can be useful for sunset shots, for example.

Light pollution filters are available in a variety of types, including screw-in filters, drop-in filters, and clip-in filters, and can be made from materials such as glass or aluminium alloy. When choosing a light pollution filter, it is important to consider the type of camera and lens you are using, as well as the specific light pollution you are trying to counter. For example, if you are shooting in an area with yellow sodium vapour lights, you will need a filter that blocks light around 589nm.

Some drawbacks of using light pollution filters include a reduction in light transmission, which may require an increase in shutter speed or ISO to compensate, and the potential for lower image quality due to the addition of another piece of glass in front of the lens. Higher-quality filters can help to minimise these adverse effects.

• Irix Edge Light Pollution Filter: This premium filter targets yellow light and features a durable design with anti-reflective coatings. It is available in a range of sizes, including an 86mm option that uses toughened glass for extra protection.
• Hoya Starscape Light Pollution Cut Filter: This slim, screw-on filter from Hoya reduces yellowish and greenish colour casts caused by street lights, improving overall contrast and natural colour. It is available in a broad range of sizes and is compatible with wide- and super wide-angle lenses.
• K&F Concept Natural Night Light Pollution Filter: This filter is designed to reduce the impact of conventional street lighting by blocking yellow and orange wavelengths of light. It features a slim, scratch- and water-resistant design made from aviation-grade aluminium alloy. It is available in round and square designs to fit standard filter holder systems.
• Rollei Astroklar Round Light Pollution Filter: This filter is made from high-quality optical glass and provides night-time images with a cooler tone by behaving neutrally within the infrared light range. It has a water- and oil-repellent surface to prevent unwanted reflections.

By using a light pollution filter during the daytime, you can enhance the overall contrast of your images and improve the saturation of certain colours, resulting in clearer and more vibrant photographs.

Frequently asked questions