Resolving power is the ability of the human eye, a camera lens, or photographic emulsion to distinguish fine details in an image. In photography, the clarity and quality of the final image depend on the combined resolving power of the lens and the light-sensitive emulsion or sensor.
Resolving power is typically expressed in terms of lines per millimeter (lp/mm), indicating the finest lines that can be distinctly recorded or visually separated in the image. Higher resolving power allows photographers to capture sharper, more detailed images, making it a crucial factor in lens selection, film choice, and overall image quality assessment.