A depth of field scale is a marking on a camera lens that shows the range of distances within which the subject will appear acceptably sharp. It indicates the nearest and furthest points that will be in focus at a given aperture setting, helping photographers plan compositions and control focus. Depth of field scales are particularly useful in landscape, macro, and zone-focusing photography, where precise focus across multiple subjects or distances is important. Understanding how to read the scale allows photographers to maximize sharpness and ensure critical elements remain in focus without relying solely on the viewfinder.