Comparison of Pentax 16-85mm f/3.5-5.6 ED DC WR DA and Sigma 17-70mm f/2.8-4.5 DC Macro

Attribute	Pentax 16-85mm f/3.5-5.6 ED DC WR DA ×	Sigma 17-70mm f/2.8-4.5 DC Macro ×
Notes	HD Coating, SP (Super Protect) Coating, Weather-Resistant, Quick-shift Focus, Filter Window	Available AF Mounts: Sigma, Canon, Nikon, Minolta, Pentax
Magnification Ratio (x)	0.26	0.43
Filter Size (mm)	72	72
Length (mm)	94	82.5
Closest Focus (m)	0.35	0.2
Diagonal Angle of View (degree)	19.00 - 83.00	20.20 - 72.40
Focus Details	Quick-Shift system for fast changing between auto and manual focusing, with ability to manually override focus at any point	Internal
Focal Length (mm)	16.00 - 85.00	17.00 - 70.00
APS Equivalent	24.5 - 130mm	1.5x: 25.5 - 105mm; 1.6x: 27.2 - 112mm
Brand	Pentax	Sigma
Image Circle	APS-C	APS-C
Name	Pentax 16-85mm f/3.5-5.6 ED DC WR DA	Sigma 17-70mm f/2.8-4.5 DC Macro
Weight (g)	517	455
Type	Standard Zoom	Standard Zoom
Aperture (f)	3.50 - 38.00	2.80 - 22.00
Diaphragm Blades	7	7
Diaphragm Blades Type	rounded	-
Lens Construction	16 elements in 12 groups, including 1 extra-low dispersion glass element and 3 aspherical elements	15 elements in 12 groups, including 1 SLD and 2 aspherical elements
Zoom System	Rotary	Rotary with lock
Diameter (mm)	78	79