When placed in front of a camera, they can transform a flat image into one with deep vibrancy and contrast. They can darken blue skies, increase saturation of foliage, and allows you to manage reflections or reduce glare.

Simply put, it reduces the amount of reflected light that goes into your lens and thereby reduces haze, while still allowing you to capture a clear image. This effect is unique to a polarising filter and cannot be replicated in post-processing.

How does it work?

Since reflections and sky-light tend to be at least partially linearly-polarised, a linear polarizer can be used to change the balance of light in the photograph. The rotational operation of the filter is adjusted for the preferred artistic effect.

For modern cameras, a circular polariser is used. This works by combining a linear polariser to create the artistic effect, followed by a quarter-wave plate to generate circularly polarised light. This helps avoid issues with autofocus and light metering sensors in some cameras.

Types of Polarising Filters

Warm Filter: Good for shooting hazy scenes. Adds a subtle yellow or reddish tone, cutting through the haze to create clearer photos with a natural appearance.
Neutral Filter: They produce a slightly cooler tone. They let you maintain colour fidelity while still highlighting the natural colours of the scene.

When to not use polarising filters

When you want to highlight wet surfaces or reflections
When in low-light, since they reduce light by about two to three f-stops. e.g. When shooting at Blue Hour, shooting at night, or photographing the Aurora Borealis
When shooting rainbows at iconic locations like waterfalls - since they either minimize the effect of the rainbow, or create an unrealistic effect if used to enhance its colours.

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