Comparison of Canon EF-S 17-85mm f/4-5.6 IS USM and Sigma 28-70mm f/2.8 DG DN Contemporary

Attribute	Canon EF-S 17-85mm f/4-5.6 IS USM ×	Sigma 28-70mm f/2.8 DG DN Contemporary ×
Aperture (f)	4.00 - 32.00	2.80 - 22.00
Filter Size (mm)	67	67
Notes	EF-S lens mount, exclusively for EOS 20D, Digital Rebel, and newer bodies with APS-C sensors.	Available AF Mounts: L-Mount, E-Mount; Dust- and splash-proof at lens mount
Closest Focus (m)	0.35	0.19
Magnification Ratio (x)	0.2	4.6
Diameter (mm)	78	72.2
Type	Standard Zoom	Standard Zoom
APS Equivalent	27 - 136mm	42 - 105mm
Diaphragm Blades	6	9
Image Circle	APS-C	35mm
Focal Length (mm)	17.00 - 85.00	28.00 - 70.00
Brand	Canon	Sigma
Name	Canon EF-S 17-85mm f/4-5.6 IS USM	Sigma 28-70mm f/2.8 DG DN Contemporary
Weight (g)	475	470
Diagonal Angle of View (degree)	18.40 - 78.50	34.30 - 75.40
Lens Construction	17 elements in 12 groups, including 1 aspherical element	16 elements in 12 groups, including 2 FLD, 2 SLD and 3 aspherical elements; Super Multi-Layer Coating, Nano Porous Coating.
Zoom System	Rotary	Rotary
Length (mm)	92	101.5
Diaphragm Blades Type	-	rounded
Focus Details	Inner focusing; full-time manual focus and USM	Internal focus with stepping motor; AF/MF switch; Supports DMF, AF+MF on Sony cameras