The Tamron TAP-in console for Canon enables you to upgrade the firmware and fine-tune select Canon mount Tamron lenses. Upgrading and fine-tuning can be done by attaching the TAP-in Console to a compatible Canon EF mount lens and a PC or MAC with an internet connection running the free dedicated downloadable software (Tamron TAP-in Utility).Camera manufacturers are always adding new functions and improvements into their products. Firmware upgrades helps to ensure that your Tamron lenses function properly on new camera bodies.Lens adjustments includes: focus adjustment, focus distance limiter customisation, VC adjustment (only on VC lenses), and full-time manual focus override