Comparison of Pentax 28-105mm f/3.5-5.6 ED D FA HD DC WR and Sigma 24-135mm f/2.8-4.5 Aspherical IF

Attribute	Sigma 24-135mm f/2.8-4.5 Aspherical IF ×	Pentax 28-105mm f/3.5-5.6 ED D FA HD DC WR ×
Notes	Available AF Mounts: Sigma, Canon, Nikon, Minolta, Pentax	WR (Weather Resistant); Included Accessories: Lens Hood PH-RBC62, Lens Cap O-LC62, Lens Mount Cap K.
Magnification Ratio (x)	0.22	0.22
Filter Size (mm)	77	62
Length (mm)	90.9	86.5
Closest Focus (m)	0.5	0.5
Diagonal Angle of View (degree)	18.20 - 84.10	23.50 - 75.00
Focus Details	Internal	DC Motor; Internal with "Quick Shift" AF/MF mechanism
Focal Length (mm)	24.00 - 135.00	28.00 - 105.00
APS Equivalent	1.5x: 36 - 202.5mm; 1.6x: 38.4 - 216mm	43 - 161mm
Brand	Sigma	Pentax
Image Circle	35mm	35mm
Name	Sigma 24-135mm f/2.8-4.5 Aspherical IF	Pentax 28-105mm f/3.5-5.6 ED D FA HD DC WR
Weight (g)	530	463
Type	Standard Zoom	Standard Zoom
Aperture (f)	2.80 - 32.00	3.50 - 38.00
Diaphragm Blades	9	9
Diaphragm Blades Type	-	rounded
Lens Construction	16 elements in 15 groups, including 2 aspherical and 1 SLD elements	15 elements in 11 groups, including 1 ED (Extra-low Dispersion) element, 1 anomalous-dispersion glass element and 2 aspherical elements; HD coating
Zoom System	Rotary	Rotary
Diameter (mm)	83.6	73