Comparison of Pentax 50-200mm f/4-5.6ED SMC DA WR and Sigma 55-200mm f/4.5-5.6 DC

Attribute	Sigma 55-200mm f/4.5-5.6 DC ×	Pentax 50-200mm f/4-5.6ED SMC DA WR ×
Notes	Available AF Mounts: Canon, Nikon, Pentax, Sigma, Sony, Four-Thirds; HSM version available for Nikon mount	Weather-resistant construction. Included Accessories: Lens Hood
Magnification Ratio (x)	0.22	0.24
Filter Size (mm)	55	49
Front Element Rotation	-	-
Closest Focus (m)	1.1	1.1
Zoom System	Rotary	Rotary
Type	Telephoto Zoom	Telephoto Zoom
APS Equivalent	1.5x: 82.5 - 300mm; 1.6x: 88 - 320mm	75 - 300mm
Diaphragm Blades	8	6
Image Circle	Image Circle	APS-C
Focal Length (mm)	55.00 - 200.00	50.00 - 200.00
Brand	Sigma	Pentax
Name	Sigma 55-200mm f/4.5-5.6 DC	Pentax 50-200mm f/4-5.6ED SMC DA WR
Weight (g)	310	285
Aperture (f)	4.50 - 22.00	4.00 - 32.00
Lens Construction	12 elements in 9 groups	11 elements in 10 groups, including 1 ED element
Diagonal Angle of View (degree)	7.10 - 25.50	8.10 - 31.50
Length (mm)	87.1	79.5
Diameter (mm)	71.5	69
Focus Details	Internal; HSM version available for Nikon mount	"Quick Shift" AF/MF mechanism