Comparison of Pentax 16-85mm f/3.5-5.6 ED DC WR DA and Tamron SP AF 28-75mm f/2.8 XR Di LD Aspherical IF

Attribute	Pentax 16-85mm f/3.5-5.6 ED DC WR DA ×	Tamron SP AF 28-75mm f/2.8 XR Di LD Aspherical IF ×
Notes	HD Coating, SP (Super Protect) Coating, Weather-Resistant, Quick-shift Focus, Filter Window	Available mounts: Canon, Minolta-D, Nikon-D, Pentax; Includes petal type lens hood.
Magnification Ratio (x)	0.26	0.26
Filter Size (mm)	72	67
Length (mm)	94	92
Closest Focus (m)	0.35	0.33
Diagonal Angle of View (degree)	19.00 - 83.00	32.00 - 75.00
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	28.00 - 75.00
APS Equivalent	24.5 - 130mm	1.5x: 42 - 112.5mm; 1.6x: 44.8 - 120mm
Brand	Pentax	Tamron
Image Circle	APS-C	Image Circle
Name	Pentax 16-85mm f/3.5-5.6 ED DC WR DA	Tamron SP AF 28-75mm f/2.8 XR Di LD Aspherical IF
Weight (g)	517	510
Type	Standard Zoom	Standard Zoom
Aperture (f)	3.50 - 38.00	2.80 - 32.00
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	16 elements in 14 groups, including one Extra Refractive Index element, four Aspherical elements and three Low Dispersion elements
Zoom System	Rotary	Rotary, telescoping
Diameter (mm)	78	73