Macro photography

Macro photography, also called photomacrography or macrography, and sometimes macrophotography, is extreme close-up photography in which the subject is reproduced at greater than its actual size. Macro photographs usually feature very small subjects and living organisms like insects.

Definitions

The optical reproduction ratio is the subject size captured on the film frame (or image sensor) compared to the actual subject size, and is a function of the lens design. The optical magnification m is equivalent to optical reproduction ratio. For example, an optical reproduction ratio of 1:10 means the image is recorded at 1⁄10th of the actual subject size, and the equivalent optical magnification is 1⁄10×, 0.10×, or 10%. In the strictest definition, a macro photograph is one in which the size of the image captured is life-size or larger (i.e., optical reproduction ratio ≥ 1:1) compared to the original subject.

Building on this, a macro lens is therefore a lens capable of optical reproduction ratios of 1:1 or greater (e.g., 2:1, 3:1, etc.). Rudolf Kingslake gives a broader definition of a macro lens as one "which is well corrected for use over a wide range of object distances."

Since the size of the image on the negative or image sensor rarely is the subject of discussion except in technical photography and film-based processes, the final image (e.g., as printed, displayed in a magazine, or on a web page) is a more relevant measure of displayed size. Define the final magnification M (or final reproduction ratio) as the image size on the final print divided by the original object size. This definition of final reproduction ratio compares the size of the finished image, as displayed, with the actual size of the subject.