Comparison of Sigma 17-50mm ƒ/2.8 EX DC OS HSM and Tamron SP AF 17-50mm ƒ/2.8 XR Di II VC LD Aspherical IF

Attribute	Tamron SP AF 17-50mm ƒ/2.8 XR Di II VC LD Aspherical IF ×	Sigma 17-50mm ƒ/2.8 EX DC OS HSM ×
Aperture (f)	2.80 - 32.00	2.80 - 22.00
Filter Size (mm)	72	77
Notes	Vibration Compensation (VC) Image Stabilization; Available AF mounts: Canon, Nikon; Includes petal type lens hood.	Image Stabilized (except for Pentax and Sony mounts). Available AF Mounts: Canon, Nikon, Pentax, Sigma, Sony. Included Accessories: Case, Petal-type
Closest Focus (m)	0.29	0.28
Magnification Ratio (x)	0.21	0.2
Zoom System	Rotary	Rotary with lock
Type	Standard Zoom	Standard Zoom
APS Equivalent	1.5x: 25.5 - 75mm; 1.6x: 27.2 - 80mm	1.5x: 26 - 75mm; 1.6x: 27 - 80mm
Diaphragm Blades	7	7
Image Circle	Image Circle	APS-C
Focal Length (mm)	17.00 - 50.00	17.00 - 50.00
Brand	Tamron	Sigma
Name	Tamron SP AF 17-50mm ƒ/2.8 XR Di II VC LD Aspherical IF	Sigma 17-50mm ƒ/2.8 EX DC OS HSM
Weight (g)	570	565
Diaphragm Blades Type	rounded	rounded
Lens Construction	19 elements in 14 groups, including Low Dispersion and Aspherical elements	17 elements in 13 groups, including 2 FLD glass elements
Diagonal Angle of View (degree)	31.20 - 78.80	27.90 - 72.40
Length (mm)	94.5	91.8
Diameter (mm)	79.6	83.5
Focus Details	Internal, with built-in focus motor	Internal, with Hyper-Sonic Motor; AF/MF switch