Comparison of Pentax SMC P-FA 24mm f/2 and Sigma 20mm f/1.8 EX DG Aspherical RF

Attribute	Sigma 20mm f/1.8 EX DG Aspherical RF ×	Pentax SMC P-FA 24mm f/2 ×
Magnification Ratio (x)	0.25	-
Type	Wide Prime	Wide Prime
Notes	Available AF Mounts: Sigma, Canon, Nikon, Minolta, Pentax	-
Name	Sigma 20mm f/1.8 EX DG Aspherical RF	Pentax SMC P-FA 24mm f/2
Weight (g)	520	405
Diameter (mm)	88.6	74
Brand	Sigma	Pentax
APS Equivalent	1.5x: 30mm; 1.6x: 32mm	36mm
Focal Length (mm)	20.00	24.00
Closest Focus (m)	0.2	0.3
Lens Construction	13 elements in 11 groups, including 2 aspherical elements	11 elements in 9 groups
Filter Size (mm)	82	67
Aperture (f)	1.80 - 22.00	2.00 - 22.00
Diagonal Angle of View (degree)	94.50	84.00
Focus Details	Internal (Rear Focus) with Dual Focus mechanism	-
Image Circle	35mm	35mm
Diaphragm Blades	9	-
Length (mm)	89.5	66