Low-Pass Filter USA - Photography Terms & Glossary

Glossary Of Photography Terms [1]

Low-Pass Filter A low-pass filter is an optical filter used in digital cameras to reduce or eliminate moiré patterns and aliasing artifacts that can occur when photographing subjects with fine, repetitive patterns, such as textiles or architectural details. Moiré patterns and aliasing artifacts are caused by interference between the pixel grid of the camera sensor and the fine details in the subject, resulting in unwanted visual artifacts and distortion in the final image.

Low-pass filters work by selectively blurring or diffusing high-frequency details in the image, effectively smoothing out sharp transitions and reducing the likelihood of moiré patterns and aliasing artifacts. Some digital cameras feature optical low-pass filters built into the sensor assembly, while others use software-based anti-aliasing algorithms to achieve similar results. In recent years, some camera manufacturers have opted to remove low-pass filters from their camera designs to maximize sensor resolution and image sharpness, relying instead on advanced image processing algorithms to mitigate moiré patterns and aliasing artifacts in post-processing.