Comparison of Pentax SMC P-DA 12-24mm f/4 ED AL IF and Tamron SP AF 17-35mm f/2.8-4 Di

Attribute	Pentax SMC P-DA 12-24mm f/4 ED AL IF ×	Tamron SP AF 17-35mm f/2.8-4 Di ×
Filter Size (mm)	77	77
Notes	Included Accessories: Lens Hood	Available mounts: Canon, Minolta-D, Nikon-D, Pentax; Includes petal type lens hood.
Closest Focus (m)	0.3	0.3
Magnification Ratio (x)	0.12	0.19
Type	Wide Zoom	Wide Zoom
Length (mm)	87.5	86.5
APS Equivalent	18 - 36mm	1.5x: 25.5 - 52.5mm; 1.6x: 27.2 - 56mm
Zoom System	Rotary	Rotary
Image Circle	APS-C	Image Circle
Focal Length (mm)	12.00 - 24.00	17.00 - 35.00
Brand	Pentax	Tamron
Name	Pentax SMC P-DA 12-24mm f/4 ED AL IF	Tamron SP AF 17-35mm f/2.8-4 Di
Weight (g)	430	440
Aperture (f)	4.00 - 22.00	2.80 - 22.00
Diaphragm Blades	8	7
Diagonal Angle of View (degree)	61.00 - 99.00	63.00 - 104.00
Lens Construction	13 elements in 11 groups, including 2 aspherical and 1 ED elements	14 elements in 11 groups, including one Low Dispersion and three aspherical elements
Diameter (mm)	84	83.2
Focus Details	Internal with "Quick Shift" AF/MF mechanism	Internal