What do you do with a Focus Control?
You don’t need a focus control, if your originals really lie perfectly flat on your flatbed. However, using filmholders slightly lifts your originals, slide mounts are of different thicknesses and also filmstrips inserted to film scanners are not always perfectly flat, the focus can vary from frame to frame. Setting an appropriate focus leads to crisp and sharp images.
A flatbed scanner offering a manual focus control may also be used to digitize certain three-dimensional objects like coins. Using the SilverFast focus control, the focus can be set so precisely that flatbed scanners can also be used for scientific work, as the example of the bird feather project impressively shows.