This week Sigma Corp have announced 17-70mm F/2.8/-4 DC Macro OS HSM lens, available from January 2010 with a suggested retail price of £399:99. Equipped with an OS (Optical Stabaliser) capability (up to 4 stops correction, this general purpose standard coverage lens, also features a useful 22cm (8.6-inch) closest focus capability.
A further point about this capability is that the minimum distance remains constant so it is claimed across all focal lengths. May not sound much but many lenses have a quoted minimum focus distance that changes as you adjust focal length. An aspheric lens element and one ELD (Extra Low Dispersion) glass element should I am presuming keep flatness-of -field and other optical defects to a minimum in the case of the first. The second will minimise colour fringing. If you would like to know more about these and other optical terms please take a look at our ‘information’ pages. The 17-70mm F/2.8/-4 DC The Image circle of the lens makes it suitable for the Nikon DX format or similar APS sensor sizes.
The 17-70mm F/2.8/-4 DC Macro OS HSM will be available in the following mounts:
Pentax (If the model used does not support HSM then Autofocus is also inactive).
The new lens has the following quoted main specification:
Focal length 17-70mm
Max/min aperture Min TBC Max f/2.8-f/22
Lens construction 17 elements in 13 groups
Picture angle 72.4º-20.2º
No. diaphragm blades 7 (rounded)
Closest focusing distance 22m/8.6 inches
Filter/attachment size 72mm
Diameter x length Approx. 79 mm x 88.9 mm