Comparison of Pentax 21mm f/3.2 AL Limited HD DA and Sony SAL-28F28 28mm f/2.8

Attribute	Sony SAL-28F28 28mm f/2.8 ×	Pentax 21mm f/3.2 AL Limited HD DA ×
Magnification Ratio (x)	0.13	0.17
Filter Size (mm)	49	43
Focus Details	-	"Quick Shift" AF/MF mechanism
Closest Focus (m)	0.3	0.2
Lens Construction	5 elements in 5 groups	8 elements in 5 groups, including 1 hybrid aspherical element
Length (mm)	43	25
Focal Length (mm)	28.00	21.00
Diaphragm Blades Type	-	rounded
Brand	Sony	Pentax
Image Circle	35mm	APS-C
Name	Sony SAL-28F28 28mm f/2.8	Pentax 21mm f/3.2 AL Limited HD DA
Weight (g)	184	134
Type	Wide Prime	Wide Prime
Notes	Built-in Hood	Available in black or silver; Dual filter attachment design: 43mm filters on the hood, and 49mm filters on the lens (without use of the hood)
APS Equivalent	42mm	32mm
Aperture (f)	2.80 - 22.00	3.20 - 22.00
Diaphragm Blades	7	7
Diagonal Angle of View (degree)	75.00	68.00
Diameter (mm)	71	63