A variety of video cameras can be controlled by the LANC (Local Application Control Bus) port, which was invented by Sony and found on other brands such as Canon and JVC. It's a simple protocol which can be interfaced quite easily with an Arduino. Neat - so using the knowledge from a tutorial on the ControlYourCamera blog - you can now automate various video functions very easily.
Thinking of making your own LANC-automation system with an Arduino? Consider using the Freetronics LeoStick:
Apart from being one of the smallest Arduino-compatibles on the market with USB, it also has an onboard RGB LED and piezo which can be used a knock sensor and various tune and sound effects. Plus the LANC circuitry will fit on the matching protostick! For more information and to order, click here.