The Sigma APO 120-400mm F4.5-5.6 DG telephoto zoom lens is an outstanding lens in this category, an excellent optical performer with Optical Stabilization and a high speed Hyper-Sonic Motor to help you shoot amazing photos. Three SLD (Special Low Dispersion) glass elements provide optimum color correction & sharpness throughout the entire zoom range. Rear focusing system corrects for fluctuation of aberration due to focusing. Compatible with the Sigma APO Tele converters. Its reach relative to its size makes handheld photography easy to track moving subjects and it fits easily in most common camera bags for the ultimate convenience. Its close-up focusing ability makes it handy for shots of small objects such as flowers without having to change lenses. Outstanding photographs are always the outcome.
The Sigma 120-400mm telephoto zoom lens covers a telephoto range of up to 400mm, letting you bring almost any subject close for short-perspective shots. The lens employs Sigma's original Optical Stabilizer (OS) function, which gives you access to shutter speeds approximately four stops slower without blurring the image. As a result, you can capture low-light, long-distance shots such as football plays, wildlife profiles, and landscape scenes without using a tripod for each photo. In addition, the lens incorporates a Hyper Sonic Motor (HSM) for quick, high-speed autofocusing, along with a rear focus system that guarantees optimum image quality throughout the entire zoom range. And photographers will love the three special low dispersion (SLD) glass elements, which correct for chromatic aberration, and the super multilayer lens coating, which reduces flare and ghosting. Other details include a minimum focusing distance of 59.1 inches, a maximum magnification ratio of 1:4.2, and support for optical 1.4x EX DG APO and 2x EX DG APO tele converters.
Specifications

Focal length: 120-400mm
Maximum aperture: f/4.5-5.6
Lens construction: 21 elements in 15 groups
Angle of view: 20.4 to 6.2 degrees
Number of diaphragm blades: 9
Minimum aperture: f/22
Minimum focusing distance: 59.1 inches
Maximum magnification: 1:4.2
Filter size: 77mm
Hood type: Bayonet
Mount: Nikon
Dimensions: 3.6 inches in diameter and 8 inches long
Weight: 61.7 ounces
Warranty: 1 year