That's awesome that you were able to see it, change lenses and still get a great picture! I think the burn was supposed to last 1 minute? The telemetry data was out there weren't very public about timing, so I don't think many people knew when the final burn would occur.
I was watching the launch live (online) and got really into it. One of the cooler things I've seen in a while.
It was so exciting to see it glow and then to watch the plume expand. On pretty much any other night I would've been way more prepared, but I haven't torn all my gear down from my last trip yet and figured I'd just bring less stuff with me. Photographing rocket launches at night has to be some of the coolest things to see.
You don't often get to actually see a spaceship or rocket 7000km away, either!