Use of UV filters taking climate and environmental factors into account

on December 14, 2021

UV lay

Many photographers prefer to use UV filters rather than Lens Protectors taking climate and environmental factors into account.

According to World Health Organization (WHO), the following environmental factors affect UV exposure.

- Time of year and time of day

- Latitude

- Altitude

- Clouds and haze

- Ozone

- Ground reflection

Solar ultraviolet rays are strongly irradiated on clear days. They are easily diffused compared to other visible light by colliding with fine water vapor or fine dirt and dust in the air, making images unclear.

Not direct rays, but many surfaces also reflect UV radiation; e.g., sand reflects about 15%, and seafoam about 25%. Many snowboarders or skiers might know that fresh snow is a perfect reflector and almost doubles a person's UV exposure.

The radiation also augments with altitude substantially by decreasing air molecules, ozone, aerosols, and clouds in the atmosphere.

With every 1000 m in altitude, UV levels increase by approximately 10%.

UV levels are higher closer to the equator, while UV levels vary mainly with the sun's height in the sky, and mid-latitudes are highest during the summer months during the 4 hours around solar noon.

(Information Source: WHO, Global warming vector created by brgfx -

While a Lens Protector provides pure protection, a UV filter prevents and reduces ultraviolet light prevalent in most outdoor circumstances.