The Sigma USB dock works in conjunction with Sigma Optimization Pro software in order to connect a photographers lens to their personal computer to update firmware and other parameters such as focus, and for the Sports category: Autofocus speeds, focus limiters, and optical stabilization functionality. Updating the firmware can be done via the internet. Sigma Photo Pro is available for Mac and PC computers.
4 Categories of customization for fixed focal length.
16 Categories of customization for zoom lenses (4 options for focal length) x (4 options for shooting distance).
AF Speed: 3 adjustment modes.
Focus Limiter: Customize auto focus range.
OS: 3 adjustment modes.
The Sigma Optimization Pro can be downloaded at the Sigma Global Vision site.