Sigma launched first standard 50mm Macro lens in 1990. This was succeeded by the 50mm F2.8 EX Macro in 1998 which proved even more popular with photographers, benefiting from improved build and optical quality. Macro lenses require a high imaging performance for photographing objects with digital SLR cameras The new advanced lens design corrects various aberrations. This macro lens is specially coated to get the best color balance whilst cutting down ghost caused by reflections from the digital image sensor. This lens provides the utmost correction against lateral chromatic aberration which is a serious problem for digital SLR cameras. Floating Focusing System Floating Focusing system that enables this lens to photograph objects precisely in entire focusing range. Standard 50mm lens for digital SLR cameras This standard macro lens enables you to enjoy the communication with subject. When viewing through the camera's finder, you are able to move your subject, and make precise adjustment. It has a close working distance and it is very convenient for taking close-up pictures of a fossil, or other inanimate things for example. This lens would have an equivalent field of view of an 85mm macro lens on a digital SLR camera (when used with the SD10). Minimum aperture of F45 Although the depth of field this medium telephoto is shallow, sometimes would be necessary to have greater depth of field, because it is difficult to take a sharp picture of a subject and the background at the maximum aperture. Minimum aperture of F45 (F45 for Sigma, Canon and Konica Minolta mounts) or F32 (F32 for Nikon and Pentax mounts) provides greater depth of field. A screw-in lens hood A screw-in hood is included, for convenient use of circular polarizing filters.