Sigma 10-20mm f/4-5.6D EX DC Lens for Sony A possesses a bright f/4-5.6D variable aperture that allows crisp imagery in difficult lighting conditions. Further, it provides improved control over the depth of field that facilitates subject isolation and enables working with selective focus techniques. Additionally, the variable f/4-5.6D aperture allows consistent performance even in the full zoom range. Finally, the variable aperture is a great weight management system too.

The EX lenses are known for their superior technology. The lens design incorporates three SLD and two aspherical elements that reduce chromatic and spherical aberrations and limit distortion. Further, the rounded seven-blade diaphragm adds smoothness and results in astounding bokeh quality. Also, the Internal Focusing design renders smooth and quick autofocus along with a non-rotating filter attachment.