Comparison of Olympus 17mm f/1.2 Pro M.Zuiko Digital ED and Sigma 20mm f/1.8 EX DG Aspherical RF

Attribute	Sigma 20mm f/1.8 EX DG Aspherical RF ×	Olympus 17mm f/1.2 Pro M.Zuiko Digital ED ×
Diagonal Angle of View (degree)	94.50	65.00
Aperture (f)	1.80 - 22.00	1.20 - 16.00
Diaphragm Blades Type	-	circular
Filter Size (mm)	82	62
Notes	Available AF Mounts: Sigma, Canon, Nikon, Minolta, Pentax	Dustproof and splashproof; Included Accessories: Lens Hood (LH-66C), Lens Cap (LC-62F), Lens Rear Cap (LR-2), Lens Case (LSC-0811).
APS Equivalent	1.5x: 30mm; 1.6x: 32mm	-
Type	Wide Prime	Wide Prime
Diaphragm Blades	9	9
Lens Construction	13 elements in 11 groups, including 2 aspherical elements	15 elements in 11 groups, including 1 Super ED, 1 ED-DSA, 1 EDA, 1 Super HR, 1 aspherical and 3 ED elements
Image Circle	35mm	Image Circle
Focal Length (mm)	20.00	17.00
Brand	Sigma	Olympus
Name	Sigma 20mm f/1.8 EX DG Aspherical RF	Olympus 17mm f/1.2 Pro M.Zuiko Digital ED
Weight (g)	520	390
Diameter (mm)	88.6	68.2
Length (mm)	89.5	87
35mm Equivalent	-	34mm
Magnification Ratio (x)	0.25	0.15
Focus Details	Internal (Rear Focus) with Dual Focus mechanism	-
Closest Focus (m)	0.2	0.2