Comparison of Pentax SMC P-FA 28-105mm f/4-5.6 IF and Sigma 28-105mm f/3.8-5.6 UC-III Aspherical IF

Attribute	Pentax SMC P-FA 28-105mm f/4-5.6 IF ×	Sigma 28-105mm f/3.8-5.6 UC-III Aspherical IF ×
Aperture (f)	4.00 - 22.00	3.80 - 22.00
Diagonal Angle of View (degree)	23.50 - 75.00	23.30 - 75.40
Magnification Ratio (x)	0.18	0.18
Filter Size (mm)	62	62
Type	Standard Zoom	Standard Zoom
Closest Focus (m)	0.49	0.5
APS Equivalent	42 - 157.5mm	1.5x: 42 - 157.5mm; 1.6x: 44.8 - 168mm
Diaphragm Blades	-	7
Image Circle	35mm	35mm
Focal Length (mm)	28.00 - 105.00	28.00 - 105.00
Brand	Pentax	Sigma
Name	Pentax SMC P-FA 28-105mm f/4-5.6 IF	Sigma 28-105mm f/3.8-5.6 UC-III Aspherical IF
Weight (g)	306	275
Zoom System	Rotary	Rotary
Lens Construction	15 elements in 12 groups	13 elements in 12 groups, including 1 aspherical element
Diameter (mm)	71	71
Length (mm)	74	72.5
Notes	-	Available AF Mounts: Sigma, Canon, Nikon, Minolta, Pentax
Focus Details	Internal	Internal