Comparison of Sigma 17-35mm f/2.8-4 EX DG Aspherical HSM and Tokina 12-28mm f/4 AT-X 128 AF PRO DX

Attribute	Sigma 17-35mm f/2.8-4 EX DG Aspherical HSM ×	Tokina 12-28mm f/4 AT-X 128 AF PRO DX ×
Filter Size (mm)	77	77
Notes	Available AF Mounts: [HSM version]: Sigma, Canon, Nikon; [w/o HSM]: Minolta, Pentax	Available AF Mounts: Canon and Nikon Digital Only. Built-in AF motor for use with all Nikon DSLRs. Included Accessories: Lens Hood
Closest Focus (m)	0.27	0.25
Magnification Ratio (x)	0.22	0.2
Type	Wide Zoom	Wide Zoom
Length (mm)	88.7	90.2
APS Equivalent	1.5x: 25.5 - 52.5mm; 1.6x: 27.2 - 56mm	1.5x: 18 - 42mm;1.6x: 19.2 - 44.8mm
Zoom System	Rotary	Rotary
Image Circle	35mm	APS-C
Focal Length (mm)	17.00 - 35.00	12.00 - 28.00
Brand	Sigma	Tokina
Name	Sigma 17-35mm f/2.8-4 EX DG Aspherical HSM	Tokina 12-28mm f/4 AT-X 128 AF PRO DX
Weight (g)	560	530
Aperture (f)	2.80 - 22.00	4.00 - 22.00
Diaphragm Blades	8	9
Diagonal Angle of View (degree)	63.40 - 103.70	54.70 - 99.40
Lens Construction	16 elements in 13 groups, including 2 aspherical and 1 SLD elements	14 elements in 12 groups, including 2 aspherical and 2 SD elements
Diameter (mm)	83.5	84
Focus Details	Internal Focus; HSM with full-time manual override	Internal with One-Touch Focus Clutch mechanism; SD-M (Silent Drive-Module)