Comparison of Pentax SMC P-DA 12-24mm f/4 ED AL IF and Tamron 17-35mm f/2.8-4 Di OSD (Model A037)

Attribute	Pentax SMC P-DA 12-24mm f/4 ED AL IF ×	Tamron 17-35mm f/2.8-4 Di OSD (Model A037) ×
Filter Size (mm)	77	77
Notes	Included Accessories: Lens Hood	Available mounts: Canon EF, Nikon F; Moisture-resistant construction; Includes petal type lens hood.
Closest Focus (m)	0.3	0.28
Magnification Ratio (x)	0.12	0.2
Diaphragm Blades Type	-	circular
Type	Wide Zoom	Wide Zoom
APS Equivalent	18 - 36mm	-
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 17-35mm f/2.8-4 Di OSD (Model A037)
Weight (g)	430	459
Aperture (f)	4.00 - 22.00	2.80 - 22.00
Diaphragm Blades	8	7
Diagonal Angle of View (degree)	61.00 - 99.00	63.40 - 103.70
Lens Construction	13 elements in 11 groups, including 2 aspherical and 1 ED elements	15 elements in 10 groups, including 4 LD (Low Dispersion) and 2 GM (Glass Molded) aspherical elements BBAR (Broad-Band Anti-Reflection) coating
Diameter (mm)	84	83.2
Length (mm)	87.5	91.4
35mm Equivalent	-	1.5x: 25.5 - 52.5mm; 1.6x: 27.2 - 56mm
Focus Details	Internal with "Quick Shift" AF/MF mechanism	Internal via OSD (Optimized Silent Drive); AF/MF switch