UV and skylight filters

Advice on UV filters

What is a UV filter used for?

UV filters block ultraviolet light and thus give analog images more sharpness and contrast, primarily by ensuring freedom from reflections and preventing a blue cast. UV filters are therefore a correction filter for the lens. Another filter in this category is the skylight filter, which also filters blue light and ensures warm (reddish) colors in the images. In contrast to this is the clean filter, which ensures color-neutral images and strong contrasts without filter properties. With digital lenses, the benefits of such filters are somewhat different, as many modern lenses already provide the above-mentioned protection against reflections through high coating (application of a thin layer with lower refractive power).

Nevertheless, the UV filter is often used to protect the lens. Brands such as B+W offer filters for digital cameras for this purpose. The situation is very similar for the Skylight filter and the Clean filter. Some of these filters can be left permanently on the lens for constant protection. Although the corrective filter properties are of secondary importance in digital photography, they can still be relevant in special environments.

What should be considered when buying (coating)?

The coating is a clear quality criterion, it is usually specified in millimetres and varies in the composition of the coating, depending on which wavelengths are to be filtered out. There are also differences in the durability and scratch resistance of the filters and therefore their longevity. The sealing, on the other hand, is responsible for how securely the lens is shielded against the finest dust or moisture, and there are considerable fluctuations here. The clean filter from Marumi provides comprehensive protection against dirt, dust, sand and moisture, while clean filters from B+W do not protect against moisture, but do protect against light impacts. Hoya advertises its UV filter with anti-electrostatic properties or another protective filter model with water and oil-repellent, as well as discoloration-resistant filter lenses.

It is therefore worth comparing which filter best meets your own requirements. It is also important that the filters do not impair the actual image quality by absorbing too much light or causing image distortion due to an inaccurate fit on the lens.

How are UV filters used in photography?

In analogue photography, the filters listed are used for color correction or, in the case of the Skylight filter, to deliberately create warm colors. This effect is particularly effective in landscape and open-air photography and can be used specifically to generate special atmospheres. In digital image creation, the corrective benefit of the Skylight filter is rather limited; here a similar effect can be created with finer gradation using presettings or subsequent image processing.

UV filters are primarily used against reflections and against high levels of blue light, which occur at high altitudes and by the sea. The blue filter produces particularly sharp and brilliant colors with neutral tones. In closed rooms, the UV filter only serves to protect the lens, while the Skylight filter with its reddish tint can also be used here. The eponymous clean filter also has a color-neutral effect, which, unlike the aforementioned UV filters and Skylight filters, neither blocks blue light nor changes the coloring. This filter is mainly used to protect the lens while ensuring absolute color neutrality and is therefore a direct alternative to the UV filter if, for example, no outdoor shots are planned.