Comment by avidiax
17 hours ago
It could be a typical design that the camera and LED always have power, and the LED is switchable.
Giving the camera plus LED a separate power supply means that the camera has to boot or come online, which maybe increases the dwell time. And the camera is not visible on the USB bus when powered off.
I think there's more engineering to Apple's design than it first seems.
The thing visible on the bus is the interface chip, not the sensor. Most cameras which I've seen hardwire their activity LEDs (it is impossible to grab stills or record video without lighting up the LED) do so by connecting the activity LED to the sensor power rail. With the sensor powered off, the device is still visible on the bus but you get no usable image data.