We use the term “focus level” to refer to the area of a document or original that lies in the focus of the imaging unit. See also Focus.
By using area sensors in our systems, we reproduce a high depth of field. Therefore, our actual focus level is more of a three-dimensional construct, which allows for a certain degree of tolerance. So, unlike line scanners, for example, our scanners are not reduced to a fixed level.
However, it makes sense to work in the optimal focus level in order to achieve the best possible results. In order for the user to quickly recognize where this level is located, even with originals of different thicknesses or heights, LED lines indicate this area before the scan. Using the book cradle and a motorized height adjustment, the originals can be moved up or down to reduce or increase the distance to the image acquisition unit.