Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary Lens for Canon EF with MC-11 Mount Converter BundleSigma 150 600mm f 5 6. 3 DG OS HSM Contemporary Lens for Canon EF The Sigma 150 600 Contemporary also touts a new zoom lock switch that can be locked at any focal length and a new manual override (MO) switch is incorporated for improved focusing control. Working with the Sigma USB dock, this lens allows for maximum customization such as firmware updates and adjustments to the focus limiter, AF speed and OS view. Digital Lens Sigma's DG lenses are