Sigma 17-50mm f/2.8 EX DC OS HSM Lens Canon EF Canon Lenses EF mount 583954. The Sigma 17-50mm lens for Canon EF-mount provides a versatile focal range with bright f/2.8 aperture suitable for travel and as a general walkabout lens thanks to excellent autofocus and compact size.. Sigma. 583954. 085126583545
