Polarizing filter (CPL filter): What is it and how do you use it?

A CPL filter (circular polarizer) is a special photo filter that reduces reflected light and intensifies colors—without any post-processing. It is one of the most versatile and effective filters in photography.

What does a CPL filter do?

A CPL filter filters out polarized light—the light that is reflected off water, glass, or non-metallic surfaces, for example. This allows you to:

  • ✅ Reduce reflections on water, glass or paint
  • ✅ Display the sky in a more vibrant blue – ideal for landscape photography
  • ✅ Make green in nature appear richer and more contrasting
  • ✅ Make fine details in wet surfaces or plants visible

How to use a CPL filter?

The CPL filter is either screwed into the lens thread or—with magnetic systems— attached and freely rotatable . By rotating the filter, you can continuously adjust the intensity of the effect.

Important: The effect is strongest when the sun is at a 90-degree angle to the camera (i.e., sideways to the subject).

When is it worth using?

  • 🌳 Landscapes: Richer colors, better foliage detail
  • 💦 Water surfaces: Remove reflections or control them specifically
  • 🚗 Architecture and vehicles: Checking gloss and light reflections
  • 🏞️ Clouds and sky: Significantly more drama and contrast

Tip from the FILTER PHOTOGRAPHER®

A high-quality CPL filter should:

  • ✅ Use Ultra-HD optical glass – for maximum sharpness
  • ✅ Have a double-sided AR and AF coating – against reflections, water and dirt
  • ✅ Be ultra slim – especially important for wide-angle lenses

A good example is the magnetic CPL filter from FILTERFOTOGRAF® , which can be flexibly combined with ND or GND filters and optimally in the LC-PRO 100 filter system can be integrated.

Combination options

A CPL can be perfectly combined with other filters – for example:

FILTERFOTOGRAF® – because every detail counts.