The micro:bit can control other Bluetooth devices. For this you will need an ANDROID tablet/phone. Install the micro:bit app on your device and then do what is says in the link below.
https://www.microbit.co.uk/mobile
When you are on the app press on 'Create Scripts'. Then select the block editor and drag on the When A pressed block and When B pressed block.Under A, put a tell camera to stard recording. Then, dothe opposite to the whan B press block.