I have been playing around a LOT with paid camera apps that allow for 48MP capture in manual mode, I love your two stage shutter implementation. As many observed, iOS automatically changes/sets shutter speeds and iso’s during 48MP manual capture depending on the available lighting, REGARDLESS of what you initially set, however, I noticed some combinations that iOS accepts, and does not change (in 48MP Manual Capture):
SS + ISO
1/30 + 1000
1/40 + 800
1/60 + 400
1/125 + 125
The lowest accepted ISO is 80, and it can be paired with any faster Shutter Speed.
The slowest accepted shutter speed is 1/15, and it can be paired with any higher ISO >/=1000
I’m not sure if you can use these combinations as a reference in implementing AUTO-ISO, particularly for 48MP capture. Please implement this! Thanks!