What is Digital scan back?

A scanning back is a type of digital camera back. Digital imaging devices typically use a matrix of light-sensitive photosensors, such as CCD or CMOS technologies. These sensors can be arranged in different ways, like a Bayer filter, where each row captures RGB components, or using one full-sized layer for each color, such as the Foveon X3 sensor.

A digital scan back takes a similar approach to the second type of photosensor, but instead of using one matrix for each component, it uses one array per component. This translates to a 3xN sensor matrix, where N is typically a large number , which is then placed vertically in a holder. To take an image, the sensor travels the x axis, taking one exposure per point.