How many Gig can the microSD card be? Does the microSD card need to be class 10 or what are the requirements? How long does the battery last in standby, and how much reserve has to be available to record the full microSD? Suppose there is only 10% reserve left when someone gets in view of the camera, and you need to capture at least as much as the microSD card can hold. How long would that 10% reserve last for the highest quality recording?