What happens when you turn your Canon on? The problem is that it’s not a camera, but a computer with a screen/LCD, a keyboard with specialized buttons and switches, a couple of CPUs, RAM, a drive/flash card… and a lens in front.

Turning the camera on

  1. Turn the switch to On.
  2. Start the sensor cleaning.
  3. Load the firmware from the EEPROM to the main memory. The EEPROM is a type of non-volatile memory, that gets reprogrammed in full each time it’s changed.
  4. Load the settings from the secondary static RAM into the “registers”.
  5. Load the “current camera” configuration into the memory and the CPU. That’s the lens, the battery…
  6. Then it’s ready to take photos.

Does it happens in this order? No. The order will depend on you. The current crop of cameras can start to take photos within ½ a second of turning it on, by delaying many of these tasks.

Turning the camera off

  1. Turn the switch to Off.
  2. Write the photos to the memory card if there’s any photo in memory.
  3. Write the current settings, like shutter count, current mode and its settings… to the secondary static RAM.
  4. Clean the sensor

You can see the camera saving the photos and it’s settings by the orange led being lit. Always wait for the orange led to be finished before:

  1. Taking the flash card out
  2. Taking the main battery out

Remember all the computer crashes in the 90s and the early 2000s because people would pull the plug on their computer instead of using the shutdown procedure?