The Sigma USB Dock lets photographers to connect their SIGMA Art, Contemporary, or Sports lens to a computer, and update the lens firmware and adjust focus position and other parameters. Exclusive SIGMA Optimization Pro software makes customization easy. It is possible to select the autofocus speed and adjust the focus limiter and Optical Stabilizer (OS) function. Updating the firmware can be done via the internet (internet connection required). Sigma Photo Pro is available for Mac and PC computers.Focus Settings: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).Full-time MF Setting*It is possible to adjust the timing to operate the Full-time MF function by customizing how much rotation of the focus ring is required.* Compatible with 24mm F1.4 DG HSM Art, 50mm F1.4 DG HSM Art, 24-35mm F2 DG HSM Art, 150-600mm F5-6.3 DG OS HSM Sports, 150-600mm F5-6.3 DG OS HSM Contemporary.For Sports Line:AF Speed: 3 adjustment modes.Focus Limiter: Customize auto focus range.OS: 3 adjustment modes.* Also compatible with 150-600mm F5-6.3 DG OS HSM ContemporarySIGMA Optimization Pro is the dedicated software that enables you to connect lenses from ne.w product lines to your computer via SIGMA USB Dock, and to customize the lens with operations such as firmware update and focus adjustment. On this page, you can download the installer program SIGMA Optimization Pro 1.4.1 Windows version as well as SIGMA Optimization Pro 1.4.0 Macintosh version. Please make sure you read information about the product before starting the download.