Sigma 18-50mm f/2.8 EX DC - unknown Mount

The Sigma 18-50mm f/2.8 EX DC is a fast, constant-aperture standard zoom lens designed for APS-C digital SLRs. As part of the EX line, it offers superior build quality and optical performance compared to standard kit lenses. The f/2.8 aperture remains constant throughout the zoom range, providing excellent depth-of-field control and better performance in dim lighting conditions. Common wear points on this model include the external finish, which can wear down to a smoother texture on high-contact areas. SDS verifies the alignment of the internal elements to ensure there is no decentring, which can cause softness on one side of the frame. The autofocus should be tested for speed and accuracy, and the aperture blades inspected for any signs of oil or sluggish movement. Internal dust should be minimal for a lens of this grade.