What is moiré and when does it appear?
Moiré is a visual artifact that appears as wavy, rainbow-colored patterns on fine repetitive details like fabric weaves, brick walls, or fine mesh. It occurs when the pattern’s frequency conflicts with the sensor’s pixel grid, creating a false interference pattern that does not exist in reality.
Why moiré happens
Your camera sensor is a grid of pixels. When you photograph a subject with a fine, regular pattern (like a pinstripe suit), the pattern frequency can clash with the pixel grid frequency.
This clash creates false patterns — wavy lines, color fringes, and shimmering. It is particularly visible in video where the pattern seems to move and shimmer as the camera shifts.
Moiré is worse when the camera downsamples (reads every other line instead of every line) because this creates additional aliasing opportunities.
How cameras reduce moiré
Optical Low Pass Filter (OLPF): A filter in front of the sensor that slightly blurs the image, preventing ultra-fine patterns from reaching individual pixels. Reduces moiré but also slightly reduces sharpness.
Oversampling: Reading the full sensor resolution and downscaling to 4K averages out pattern conflicts. The most effective method without sacrificing sharpness.
No OLPF: Some cameras remove the filter for maximum sharpness, accepting moiré risk in certain situations.
Oversampling cameras at Camera Shop Egypt
How to avoid moiré in your work
If you shoot fashion or corporate video, ask subjects to avoid fine pinstripe patterns, herringbone, and tight checked fabrics. Solid colors and larger patterns are safe.
Slightly changing the camera angle or distance can shift the interference pattern out of the visible range.
In post-production, moiré can be reduced with chroma noise reduction targeting the false color patterns.
Cameras that oversample from a higher resolution sensor (reading full 6K and outputting 4K) produce the cleanest video with virtually no moiré. This is one of the most important specs for video work.