Sigma 17-70mm F2.8-4 DC OS HSM C is an Auto Focus (AF)
Standard Zoom lens with APS-C / DX max sensor coverage and it is designed to be used with Pentax KAF3 mount cameras.
Lenses in Pentax KAF3 Mount with Same Focal and Aperture Range
Lens Mount
Sigma 17-70mm F2.8-4 DC OS HSM C is compatible with cameras that have Pentax KAF3 lens mount.Some of the latest released cameras with Pentax KAF3 lens mount are
,
and
.
Sensor Coverage
Max sensor coverage of Sigma 17-70mm F2.8-4 DC OS HSM C is APS-C / DX.
Focal Range
Sigma 17-70mm F2.8-4 DC OS HSM C has a focal range of 17-70mm and 4.1X zoom ratio.
Optical Image Stabilization
Sigma 17-70mm F2.8-4 DC OS HSM C features an optical image stabilization system which helps to reduce the blur that occurs due to shaking during hand-held shooting.
Zoom Method
Sigma 17-70mm F2.8-4 DC OS HSM C 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 17-70mm F2.8-4 DC OS HSM C is a variable aperture lens with a max aperture of f2.8 and a minimum aperture of f22 at 17mm, and a max aperture of f4 and minimum aperture of f22 at 70mm .
Optical Formula
Sigma 17-70mm F2.8-4 DC OS HSM C's optical formula consists of 16 elements in 14 groups.