Comparison of Pentax 15mm f/4 ED AL Limited HD DA and Tamron 20mm f/2.8 Di III OSD M1:2 (Model F050)

Attribute	Tamron 20mm f/2.8 Di III OSD M1:2 (Model F050) ×	Pentax 15mm f/4 ED AL Limited HD DA ×
Aperture (f)	2.80 - 22.00	4.00 - 22.00
Filter Size (mm)	67	49
Notes	Available mounts: Sony E-mount; Moisture-resistant construction; Included Accessories: Flower-shaped hood, lens caps.	Hood is built-in, pullout type; Available in black or silver; High-grade multi-layer HD (High Definition) coating
Closest Focus (m)	0.11	0.18
Magnification Ratio (x)	0.5	0.15
Diameter (mm)	73	63
Type	Wide Prime	Wide Prime
APS Equivalent	-	23mm
Diaphragm Blades	7	7
Image Circle	Image Circle	APS-C
Focal Length (mm)	20.00	15.00
Brand	Tamron	Pentax
Name	Tamron 20mm f/2.8 Di III OSD M1:2 (Model F050)	Pentax 15mm f/4 ED AL Limited HD DA
Weight (g)	220	189
Diaphragm Blades Type	circular	rounded
Lens Construction	10 elements in 9 groups, including 1 GM (Glass Molded) aspherical and 3 LD (Low Dispersion) elements; BBAR coating; Fluorine coating	8 elements in 6 groups
Diagonal Angle of View (degree)	94.50	86.00
Length (mm)	64	39.5
35mm Equivalent	1.5x: 30mm	-
Focus Details	Internal with OSD (Optimized Silent Drive) motor; Continuous manual focus mechanism	Internal, with "Quick-Shift" focus system