Fujifilm has a history of experimenting with different sensor and photosite layouts to achieve greater picture quality than conventional sensors, and its new X-Trans sensor looks especially interesting, promising higher resolution and finer detail rendition.
Conventional sensors use a so-called ‘bayer pattern’ of red, green and blue photosites to capture full colour images. But this regular grid can clash with lines and textures in your subject to produce ugly moire, or interference effects. To fix this, the makers add a ‘low-pass’ or ‘anti-aliasing’ filter (3) behind the lens (1) in front of the sensor (2). This slightly blurs the fine detail, which fixes any moire but means the image needs some sharpening later and never looks completely crisp at high magnifications.
Fujifilm’s answer with the X-Trans sensor is to try to mimic the random arrangement of silver halide grains in film, where moire was never a problem. The company has done this by replacing the regular 4 x 4 grid of red, green and blue photosites with a 6 x 6 grid. This more irregular pattern reduces moire problems to the extend that a low-pass or anti-aliasing filter is no longer necessary – and this mean that fine detail is rendered with a crispness that conventional sensors can’t quite match.
Fujifilm also claims that the revised arrangement of red, green and blue pixels improves colour accuracy since every row and column contains a mix of red, green and blue pixels – that’s not the case with a conventional bayer pattern.