Comparison of Pentax 18-270mm f/3.5-6.3 ED SDM SMC DA and Tamron AF 18-250mm f/3.5-6.3 Di II LD Aspherical IF Macro

Attribute	Pentax 18-270mm f/3.5-6.3 ED SDM SMC DA ×	Tamron AF 18-250mm f/3.5-6.3 Di II LD Aspherical IF Macro ×
Notes	Autofocus supported on K10D and later bodies. Optional Accessories: PH-RBD lens hood, S80-120 case.	Available AF Mounts: Canon, Nikon, Pentax, Sony; Included Accessories: Lens Hood
Magnification Ratio (x)	0.26	0.29
Filter Size (mm)	62	62
Length (mm)	89	84.3
Closest Focus (m)	0.45	0.45
Diagonal Angle of View (degree)	6.00 - 76.00	6.40 - 75.60
Focus Details	Internal with supersonic AF motor (SDM)	Internal
Focal Length (mm)	18.00 - 270.00	18.00 - 250.00
APS Equivalent	27.5 - 414mm	1.5x: 27 - 375mm; 1.6x: 28.8 - 400mm
Brand	Pentax	Tamron
Image Circle	APS-C	APS-C
Name	Pentax 18-270mm f/3.5-6.3 ED SDM SMC DA	Tamron AF 18-250mm f/3.5-6.3 Di II LD Aspherical IF Macro
Weight (g)	453	430
Type	Standard Zoom	Standard Zoom
Aperture (f)	3.50 - 45.00	3.50 - 22.00
Diaphragm Blades	7	7
Diaphragm Blades Type	rounded	-
Lens Construction	16 elements in 13 groups, including 2 ED and 2 aspherical elements	16 elements in 13 groups, including 1 LD (Low Dispersion), 1 AD (Anomalous Dispersion) and 2 aspherical elements
Zoom System	Rotary, with lock switch	Rotary
Diameter (mm)	75.8	74.4