Depth of Field
From Opticon Technical Support Knowledge Base
In barcode scanning, like in optics or photography, depth of field (DOF) is the distance between the nearest and farthest objects that appears acceptably sharp. A lens can precisely focus at only one distance at a time, as you move farther from the focal point sharpness gradually decreases. Within the DOF the image read by the scanner is sharp enough for successful barcode scanning.
