Comparison of Canon EF 400mm f/2.8L IS USM and Sigma 200-500mm f/2.8 EX DG APO

Attribute	Sigma 200-500mm f/2.8 EX DG APO ×	Canon EF 400mm f/2.8L IS USM ×
Filter Size (mm)	72	52
Notes	Available AF Mounts: Sigma, Canon, Nikon; The dedicated 2x "Attachment" ensures autofocusing at the 1000mm focal length.	Image Stabilization
Closest Focus (m)	2	3
Magnification Ratio (x)	0.13	0.15
Type	Telephoto Zoom	Telephoto Prime
Focus Details	Internal	Inner focusing; full-time manual focus and USM
APS Equivalent	1.5x: 300 - 750mm; 1.6x: 320 - 800mm	640mm
Diameter (mm)	236.5	163
Image Circle	35mm	35mm
Focal Length (mm)	200.00 - 500.00	400.00
Brand	Sigma	Canon
Name	Sigma 200-500mm f/2.8 EX DG APO	Canon EF 400mm f/2.8L IS USM
Weight (g)	15700	5370
Aperture (f)	2.80 - 22.00	2.80 - 32.00
Diaphragm Blades	9	8
Diagonal Angle of View (degree)	-	6.20
Length (mm)	726	349
Zoom System	Power Zoom	-
Lens Construction	17 elements in 13 groups, including SLD and 3 ELD elements	17 elements in 13 groups, including 1 flourite and 2 UD elements