Macrophotography is close-up photography, usually of very small subjects, in which the size of the subject in the photograph is greater than life size. Classically a macrophotograph is one in which the size of the subject on the negative or image sensor is life size or greater. However in modern use it refers to a finished photograph of a subject at greater than life size. The ratio of the subject size on the film plane (or sensor plane) to the actual subject size is known as the reproduction ratio. Likewise, a macro lens is classically a lens capable of reproduction ratios greater than 1:1, although it often refers to any lens with a large reproduction ratio, despite rarely exceeding 1:1.

Outside of technical photography and film-based processes, where the size of the image on the negative or image sensor is the subject of discussion, the finished print or on-screen image more commonly lends a photograph its macro status. For example, when producing a 6×4 inch (15×10 cm) print using 135 format film or sensor, a life-size result is possible with a lens having only a 1:4 reproduction ratio.