Sigma Telephoto 180mm f/3.5 EX APO Macro DG HSM Autofocus Lens for Nikon AF-D

Taking picture of small animals and insects can be difficult, because they often run or fly away, or can be dangerous or become aggressive if you approach them. Therefore it is advantageous to have a greater working distance between the camera and such subjects. Longer focal length lens can provide this greater distance, but most long lens do not focus close enough to provide a large image of small subjects. The tele-macro type lens solves this problem by producing a large, high quality image, up to life-size, while maintaining a long working distance. This can enable you to capture on film the world of photomicrography, without disturbing the subjects. The 180mm F3.5 APO MACRO lens has a very narrow field of view, and can allow very narrow depth-of-field for selective focus and less distracting backgrounds. This lens is most desirable for photographers who are serious about producing high quality images both of macro subjects at life-size reproduction, as well as normal telephotography. Floating Inner Focusing System The Floating Inner Focus System of the APO MACRO 180mm F3.5 EX HSM provides high quality optical performance and superior handling and stability. This system moves two lens groups within the lens, so the lens' physical length remains unchanged. This technique also maintains good correction for Spherical Aberration and Astigmatism, and provides extremely high optical performance from infinity to 1:1 Macro. Full-time Manual Focus with HSM Macro photography requires precise focus adjustment. The HSM (Hyper Sonic Motor) feature is ideal for this purpose as it allows quick and precise manual focus, even in auto focus mode. Simply focus with HSM auto focus, then while partially depressing the shutter release, turn the manual focus ring until any desired focus adjustment is made. Then depress the shutter release fully to take the picture. It is not necessary to switch from AF to MF. When the shutter release is next depressed, the AF function will resume. Of course the AF function can be disabled altogether