>>3853440>The a7ii went from off to a photo focused and taken in 2.1 seconds
When an A7II has been off for a little bit longer, it requires more startup time.
I just tried it with my own. The first shot took about 8 seconds. I turned it off and back on again it it was closer to 2 seconds like you said.
I'm guessing it's normally in a sort of sleep mode that it can wake up from more quickly, but it goes into full shutdown when left alone for long enough. Try popping the battery out and back in for a full startup time and time it again.
Notably: That 2 second startup time is the same even if it's just gone into power-switch-still-on-but-haven't-taken-a-picture-in-a-bit sleep mode, not just if you've switched it off. So if you have it "turn off" after a few seconds to save on battery life, you still get that.
Compare to DSLRs. I actually *also* have a Nikon D70, but it's been so long since I've actually touched it that the battery is currently dead and I don't remember where the charger is. So I'll try with a random selection of DSLRs I have in arm's reach which do have a charge:
Nikon D700: Took a picture before I could count to 1
Canon 5D3: Took a picture before I could count to 1
Canon 40D: Took a picture before I could count to 1.
Canon Rebel (original, 300D): About 5 seconds
So yeah, a D70 is about as ancient as a DSLR can get--it was Nikon's first "midrange" body. I'm guessing it's just slow as hell. Any DSLR made within the last 15 years or so is going to start up faster than your brain can process, so it feels instant.
Notably, I've also got an X-T1, a Panasonic GF5, and an A6000 in grabby range, and those all have a noticeable (if low) startup time as well.
Also interesting: I've got a Sony a33, which is one of their A-mount SLTs (i.e., like an SLR but the mirror doesn't flap out of the way and it uses an EVF), and that's somewhere between the startup time of a DSLR and a full mirrorless.