Sigma 70-300mm F4-5.6 DG OS is an Auto Focus (AF)
Telephoto Zoom lens with 35mm FF max sensor coverage and it is designed to be used with Sony Alpha mount cameras.
Lenses in Sony Alpha Mount with Same Focal and Aperture Range
Lens Mount
Sigma 70-300mm F4-5.6 DG OS is compatible with cameras that have Sony Alpha lens mount.Some of the latest released cameras with Sony Alpha lens mount are
Sony A99 II,
Sony A68 and
Sony A77 II.
Sensor Coverage
Max sensor coverage of Sigma 70-300mm F4-5.6 DG OS is 35mm FF.
Focal Range
Sigma 70-300mm F4-5.6 DG OS has a focal range of 70-300mm and 4.3X zoom ratio. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 105 - 450mm.
Optical Image Stabilization
Sigma 70-300mm F4-5.6 DG OS features an optical image stabilization system which helps to reduce the blur that occurs due to shaking during hand-held shooting.
Zoom Method
Sigma 70-300mm F4-5.6 DG OS features Rotary (extending) zoom method where the length of the lens changes as you zoom in or out. This makes it possible to design the lens with a smaller minimum length ( generally when it is zoomed out) compared to internal zoom lenses. The disadvantages of this design are being harder to seal against dust and moisture, weight balance shifting while zooming and zoom creep in certain lenses.
Aperture
Sigma 70-300mm F4-5.6 DG OS is a variable aperture lens with a max aperture of f4 and a minimum aperture of f22 at 70mm, and a max aperture of f5.6 and minimum aperture of f32 at 300mm .
Optical Formula
Sigma 70-300mm F4-5.6 DG OS's optical formula consists of 16 elements in 11 groups.