Sigma USB dock for Sony A lens bayonet

SIGMA USB DOCK By connecting the USB cable to a computer, the SIGMA USB DOCK enables photographers to update the lens firmware and customise features of the lens to their requirements. The adjustment is processed with specially designed software, SIGMA Optimization Pro, which is available as a free download from Sigma's website. Users will be able to update lens firmware, ensuring their lens is never "out of date". Fine focus adjustments are also possible at varying positions of the lens' focal range and focus positions ensuring the focus matches your camera precisely at every zoom and focus position. Sigma's "Sports" lenses also allow further customisation of the AF speed, Optical Stabilisation and Focus Limiter position. Customisation for Art, Sports and Contemporary lenses: Focus Adjustment Settings: 4 Categories of customisation for fixed focal length lenses. 16 Categories of customization for zoom lenses (4 options for focal length) x (4 options for shooting distance). Customisation for Sports lenses: AF Speed: 3 adjustment modes. Focus Limiter: Customize auto focus range. OS: 3 adjustment modes. This USB Dock is only compatible with Sigma's latest Global Vision, A (Art), S (Sports) and C (Contemporary) lenses. A full list of compatible lenses can be found on Sigma's website.