https://medium.com/@jdc-cunningham/making-a-user-interface-f...
A lot of pictures and full menu map
And MS paint wiring diagrams
(1st camera) https://github.com/jdc-cunningham/pi-zero-hq-cam/tree/master...
(2nd camera orange) https://github.com/jdc-cunningham/modular-pi-cam/blob/master...
I use systemd to run main.py let me time it real quick.
Edit: I was off, it's 40 seconds when the intro animation starts playing.
This is why the camera spends most of its time in the home screen state until you're ready to take a photo which is when the live pass through plays or while recording a video (allows you to change focus/aperture while filming). That also conserves power since it has the highest current draw while recording/showing a live preview.