Macro lens is a highly corrected convex lens designed for close-up photography.
The image quality is very good up to an image magnification of 1:1. The macro lenses is designed for working at close, pre defined, working distances and are corrected for aberrations at such selected working distances. As a consequence of such corrections, most of these lenses are provided with a maximum aperture of approximately f/4. These lenses are auto focus lenses. Their inner focal lengths vary between 100 to 150mm. providing comfortable working lengths. Medium telephoto macro lenses have shallow depth of field.
In macro photography the image generated by the macro lens is projected on the plane of the film and is close to the size of the object. There are 35mm macro lenses that achieve at least half the size or of equal size of the object being photographed. Another important point to be noted is that the Macro lenses produce sharp image only at the macro focus and will not give a good definition at other distances. When magnification requirement is more than unity, a bellow or extension tube is used and the lens is reverse mounted b at sharpness of the image may not be good.