Sigma USB Dock for Nikon Lens 878-306

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. 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) Sports Line: 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. Compatible Lenses: Art - 35mm F1.4 DG HSM Contemporary - 17-70mm F2.8-4 DC MACRO OS HSM / 17-70mm F2.8-4 DC MACRO HSM Sports - 120-300mm F2.8 DG OS HSM Warranty - 1 year America Warranty + 3 year USA extended warranty on manufacturing and workmanship for a total of 4 years of coverage from date of purchase. Product Specifications: For Windows:Your computer must meet the following criteria for the software to operate: Core 2 Duo or faster processor Windows 7 or Windows 8 1GB of RAM 1GB of available hard disk space 24bit or more graphics card 1024 x 768 or higher screen resolution PC with USB 1.1 port For Mac OS:Your computer must meet the following criteria for the software to operate: Mac OS X Ver.10.7 or 10.8 and Intel Core Processor 1GB of RAM 1GB of available hard disk space 24bit or more graphics card 1024 x 768 or higher screen resolution PC with USB 1.1 port