Sony boots a RTOS Linux system on their cameras in 3 seconds flat, and the firmware is arguably mission critical for that camera. It can be done for an infotainment system.
However, you don't notice that three seconds. Because when you flick the switch and raise the camera, and it's already ready to shoot.
There's powersave after a minute (configurable), which can be considered as S3 sleep, and returning from that is faster.
Moreover if you have a stabilized lens, they work in tandem to improve things even further.
Many shots you think which would gonna be blurry comes out perfect. e.g.: https://www.flickr.com/photos/zerocoder/49047642802/in/photo...
I don't really use Flickr and a new personal website remains as yet on my list for this year, but here's something from back in 2020, one of the few really good shots I got that year: https://web.archive.org/web/20230513030226/https://aaron-m.c...
Not the soul of technical perfection, I freely grant, and I'm obviously adding a fair bit of light. But this was the second or third time I'd strayed even as far as my own backyard, after a covid dose earlier in the year had me knocked back for a few months. I suppose it could be sharper, but I had a hard time catching my breath that day, and I'm not actually sorry that a little human frailty should show through in a work where impending death and the onset of life are quite literally belly to belly.
In any case, it was really switch-to-shutter lag I was curious about. Three seconds there would be an eternity, so I appreciate knowing that's not the case.