Comparison of Canon EF 300mm f/2.8L IS USM and Sigma APO 300mm ƒ/2.8 EX DG HSM

Attribute	Canon EF 300mm f/2.8L IS USM ×	Sigma APO 300mm ƒ/2.8 EX DG HSM ×
Aperture (f)	2.80 - 32.00	2.80 - 32.00
Filter Size (mm)	52	46
Notes	Image Stabilization; Magnesium alloy lens barrels	Available AF Mounts: [HSM version]: Sigma, Canon, Nikon; [w/o HSM]: Minolta, Pentax
Closest Focus (m)	2.5	2.5
Magnification Ratio (x)	0.13	0.13
Type	Telephoto Prime	Telephoto Prime
Focus Details	Inner focusing; full-time manual focus and USM	Internal; HSM with full-time manual override
APS Equivalent	480mm	1.5x: 450mm; 1.6x: 480mm
Diaphragm Blades	8	9
Image Circle	35mm	35mm
Focal Length (mm)	300.00	300.00
Brand	Canon	Sigma
Name	Canon EF 300mm f/2.8L IS USM	Sigma APO 300mm ƒ/2.8 EX DG HSM
Weight (g)	2550	2400
Diagonal Angle of View (degree)	8.30	8.20
Length (mm)	252	214.5
Diameter (mm)	128	119
Lens Construction	17 elements in 13 groups, including 1 flourite and 2 UD elements	11 elements in 9 groups, including 2 ELD elements