Comparison of Sigma APO 2X EX DG and Sony SAL-20TC 2X

Attribute	Sigma APO 2X EX DG ×	Sony SAL-20TC 2X ×
Type	Teleconverter	Teleconverter
Name	Sigma APO 2X EX DG	Sony SAL-20TC 2X
Weight (g)	234	200
Image Circle	35mm	35mm
Brand	Sigma	Sony
Magnification Ratio (x)	2	2
Lens Construction	6 elements in 5 groups	6 elements in 5 groups
Notes	Available AF Mounts: Canon, Minolta, Nikon, Pentax, Sigma, Sony	Compatible Lenses: Sony 70-200mm f/2.8 G, Sony 300mm f/2.8 G and Sony 135mm f/2.8 STF
Diameter (mm)	68.5	64
Focal Length Multiplier	2X that of the master lens	2X that of the master lens
Effective Reduction in Aperture	2 f-stops	2 f-stops
Length (mm)	52	43.5