A supplementary lens is an optical accessory, also commonly referred to as a close-up lens, that is attached to the front of a camera’s primary lens to enable closer focusing distances than the lens alone allows. By modifying the optical path, a supplementary lens magnifies the subject, making it possible to capture detailed images of small objects such as flowers, insects, or intricate product details without requiring a dedicated macro lens.
Supplementary lenses come in various strengths, usually measured in dioptres, which determine the degree of magnification and the minimum focusing distance achievable. They are valued for their convenience and portability, allowing photographers to experiment with macro or close-up photography without investing in specialized equipment. While they may introduce minor optical distortions compared with purpose-built macro lenses, high-quality supplementary lenses produce sharp, detailed images suitable for casual and professional applications alike.