It's unfair to compare an idling deep sleep device with a cold boot.

However, there is a shortcut: Just don't boot a full OS (thinking of custom firmware which boots in fractions of seconds, standard in the Microcontroller world). Or boot an optimized Linux user space. I am confident with a bit fiddling one can bring down a standard SBC Linux to a few seconds from cold to ready.

The early Sony Alpha A7 cameras run Android (really: you could jailbreak and write your own PlayMemories apps)

https://github.com/ma1co/sony-pmca-re

https://photo.stackexchange.com/questions/59226/does-the-son...

So there must have been a way to do this at that time. (I suspect a simpler subsystem does initial boot response).

I did contemplate building something around one of the Arducam modules and an RP2350.

It’s possible to boot Linux in seconds, it’d just be a terrible developer experience.

Not from off state, though? Granted I still expect the iphone to boot quicker than 20 seconds.

Cameras shouldn't need to boot at all.

https://mitxela.com/projects/thermal_paper_polaroid talks about making a camera with a raspberry pi, and by using Buildroot they got it down to acceptable boot times

Sub 2-second booting Linux is generally possible, either by bundling everything into a big image or by creating a fixed hibernation file and resuming from it. That's what they do for real embedded systems, but the downside is that they tend to be monolithic and not so update or modding friendly.

1: https://www.youtube.com/watch?v=TTcP3xeLrEY

There have been attempts to make the Pi boot faster (by disabling the initialization of various subsystems), e.g.:

https://github.com/IronOxidizer/instant-pi

https://himeshp.blogspot.com/2018/08/fast-boot-with-raspberr...

https://kittenlabs.de/blog/2024/09/01/extreme-pi-boot-optimi... (previously featured here too https://news.ycombinator.com/item?id=41420597)

Things lost to time: The Minolta Dimage A1 had contacts for detecting when gripped, so it could ready itself without any button pressed: https://en.wikipedia.org/wiki/Minolta_Dimage_A1 (You see it in the pic, but its not described in the article).

i built my own camera out of a Zero 2W [0] and by disabling Picam2 and letting the OS (Debian Bullseye) idle, i can get 2 days of shots and some videos while i walk around the city/hiking out of 3 18650 batteries... bringing 3 spare batteries in my backpack never put me needing battery in any situation! starting Picam2 takes a fraction of a second

[0] https://happort.org/camera

Nice, my Google 10 I feel boots rather fast but I'd say 5sec to boot, unlock, camera +5 secs so it would be 10 for me - 3 seconds I envy you.

Comparing that to a real camera: I can "quick draw" pick up a Nikon DSLR that's off, flick the power switch and hit the shutter button one handed in one motion as fast as I can move and there's a good picture on the screen as soon as I let go of the trigger. Double click trash can and it's gone. Either will take less than half a second. Battery life is so long I usually forget to charge it. I suspect the power switch is just a "key lock" that prevents triggering anything because there's no delay. Either that or it's a wakeup in the microcontroller range of timing.

(You can easily get jank by filling up the buffer or slow memory card or autofocusing on something impossible, possibly in the dark etc, of course.)

My kid has a Fisher-Price Kid Tough camera. It's excellent for us but the pictures are so bad even the kid is disappointed.

It would be fun to repace the guts with something like this project but a long boot time is a deal breaker.

Perhaps the software can be optimised or a DIY friendly pi pico project is the way.

I agree with the premise but that's a bad comparison. If you have your iphone off, do you get to the camera in 3 seconds as well, after booting?

I bet this could be changed to seconds if a unikernel type approach were used. There’s no need to boot a full OS. I understand the developer starting with Linux, though, as I’m sure it’s easier for debugging.

you can get a zero booting under 10 seconds fairly reliably.

still slower than a hot phone with an app, but it's faster than 22s.