Bayer Arrays and Sensor Patterns: How Cameras Capture Color

Why color filter arrays exist

A camera sensor is a monochrome device. Each photosite, or pixel, measures the intensity of light that reaches it, but it cannot tell what color that light is. To record color, the sensor needs a way to distinguish wavelengths. The standard solution is a color filter array, a microscopic mosaic of red, green, and blue filters placed over the sensor surface.

Each pixel sees only the wavelengths its filter lets through. The camera processor then estimates the missing color information for every pixel using a process called demosaicing, or interpolation. This is why the arrangement of the filters matters: it determines how much information the camera has to work with and where it has to guess.

The most widely used layout is the Bayer mosaic, patented in the 1970s, which uses a repeating 2x2 pattern with one red filter, two green filters, and one blue filter. The extra green pixel mirrors the human eye's sensitivity to green light, which sits in the middle of the visible spectrum.

How the Bayer mosaic works

In a Bayer array, each 2x2 block contains one red, two green, and one blue filter. At the full resolution of the sensor, only a quarter of the pixels record red, only a quarter record blue, and half record green. The camera must interpolate to produce a full-color image at every pixel location.

Because the Bayer pattern samples color at a lower rate than brightness, the demosaicing step can introduce artifacts. Fine repeating details, such as fabric weaves or distant brickwork, can fool the interpolation and produce moiré, the rainbow-colored false patterns you sometimes see in photos.

To counter moiré, many cameras place a low-pass filter, also called an optical or anti-aliasing filter, over the sensor. This filter slightly blurs the image before it reaches the sensor, trading a small amount of sharpness for a large reduction in false color patterns. Some modern cameras omit this filter for maximum resolution and rely on the demosaicing algorithm to suppress moiré.

If you work with raw files, the demosaicing is done by your raw converter, not the camera. The software you choose can have a visible effect on how fine detail and edges are rendered. Raw format explained covers how the raw data retains the Bayer pattern until conversion.

X-Trans and other pattern variants

Fujifilm's X-Trans pattern is the most prominent alternative to Bayer. Instead of the repeating 2x2 block, X-Trans uses a larger 6x6 repeating pattern with red, green, and blue filters arranged so that no single row has the same sequence of colors repeating at short intervals. This irregular layout is designed to reduce moiré without needing a low-pass filter, which lets the sensor resolve fine detail more directly.

The visible result is that X-Trans cameras tend to render fine texture without the color artifacts that a Bayer sensor might produce at the same resolution. The trade-off is that the pattern is less standardized than Bayer, and each raw converter may interpret it slightly differently. Third-party software has improved considerably, but some conversion tools still favor the regular Bayer grid.

Other sensor technologies use different approaches. Foveon sensors, found in some Sigma cameras, stack three layers of photodiodes to capture red, green, and blue at every pixel location, avoiding interpolation entirely. Sigma has shifted its cameras to a Bayer design in recent years, which shows how deeply the industry has standardized around the mosaic approach.

There are also 'quad Bayer' patterns, sometimes called 'pixel binning' layouts, used in some high-resolution sensors and many phone cameras. These group four pixels of the same color together, allowing the camera to combine them for better low-light sensitivity and to produce lower-resolution images with less noise. See pixel binning explained for more on this approach.

What the pattern means for sharpness and moiré

The practical difference between Bayer and X-Trans comes down to two trade-offs. A Bayer sensor with a low-pass filter gives a clean, artifact-free image at the cost of some fine detail. A sensor with no low-pass filter, whether it uses Bayer or X-Trans, captures more detail but must manage moiré at the demosaicing stage.

With a Bayer sensor that has no low-pass filter, the camera or raw converter applies software correction to suppress false color. This can be very effective, but on patterns like tight weaves or distant foliage, you may still see occasional color moiré. With X-Trans, the filter arrangement itself reduces these artifacts, which is why Fujifilm has historically omitted the low-pass filter on several of its X-series cameras.

Resolution also interacts with the pattern. A 20-to-29-megapixel sensor with a strong low-pass filter will render less fine detail than a 30-to-49-megapixel sensor without one, but the lower-resolution camera may produce cleaner results on texture-heavy subjects. The pattern is one factor among many; the lens, the sensor's pixel size, and the demosaicing algorithm all contribute.

For video, the same principles apply, but the stakes are higher because moiré in a moving image is more distracting than in a still. Cameras designed for video, such as those in the Best 4K Cameras in 2026 guide, often use a low-pass filter or a sensor pattern designed to minimize artifacts in continuous footage.

What to pick for your use

For most photographers, the sensor pattern should not be the deciding factor. The difference between a well-implemented Bayer sensor and a well-implemented X-Trans sensor is visible only in specific conditions: fine repeating patterns, high-contrast edges, and when pixel-peeping at 100%.

If you photograph architecture, fabric, or other subjects with fine repetitive detail, and you want maximum edge sharpness, a camera with no low-pass filter is worth considering. Both Bayer and X-Trans designs fit this profile. The Best 30 to 49 MP Cameras in 2026 and Best 50 MP or More Cameras in 2026 guides can help you compare the latest options.

If you mainly shoot people, landscapes, or general travel photography, moiré is less likely to appear, and the sensor pattern will have little effect on your results. The same is true if you shoot in raw and process with the converter you are comfortable with, since good demosaicing software handles both patterns well.

If you are deciding between a Bayer and an X-Trans camera, look at the system around the sensor. Lens lineup, body design, autofocus, and processing are far more important to your images than the filter pattern. The Best APS-C Cameras in 2026, Best Fujifilm X Cameras in 2026, and Best Sony E Cameras in 2026 guides cover the two ecosystems where these sensors appear most often.

What to pick for your use

Questions

What is a Bayer sensor pattern?

A Bayer sensor pattern is the most common color filter array layout, using a repeating 2x2 grid of one red, two green, and one blue filter. It lets a monochrome sensor record color by measuring each pixel through a single color filter and then interpolating the missing information.

Is X-Trans better than Bayer?

X-Trans is designed to reduce moiré without a low-pass filter, which can increase perceived sharpness. In practice, the advantage is subtle and depends on the subject. A well-implemented Bayer sensor with a good demosaicing algorithm produces very similar results for most photography.

Why does moiré happen?

Moiré happens when a fine repeating pattern in the scene has a frequency higher than the sensor's sampling rate. The demosaicing algorithm interprets the pattern incorrectly and produces false color or rainbow-like artifacts. A low-pass filter blurs the detail slightly so that it falls below this threshold.

Does the sensor pattern affect image quality?

It can affect fine detail, moiré, and false color, but the effect is magnified only in specific conditions such as photographing fabric or architecture at certain angles. For most subjects and prints, the lens, light, and processing have a larger impact on the final image.

Do all cameras use a Bayer pattern?

No. Fujifilm uses X-Trans on some of its cameras, and other alternative designs exist. However, the vast majority of interchangeable-lens cameras, compact cameras, action cameras, and phone cameras use a Bayer mosaic or a variant of it.