1. I must check it out if this can be overriden
2. It's normal behaviour. Frames come in as much as the shutter speed is. Most camera applications limit the shutter speed when on viewfinder mode so that the experience is better but this comes at the expense of not knowing beforehand how shaken your photo will be. I wanted to provide the most raw experience possible so that is going to stay. The fact that when you turn the phone to a lighter spot it takes some time to adjust is due to the same reason. Exposure data comes in with each frame, so it goes like this 1s -> data came in, rawcam decides it needs to adjust down -> 0,5s (it does not adjust right away to avoid flicker) -> more adjustment needed -> 0.25s -> 0.12s -> from now on things happen fast enough. Total time 1+0.5+0.25+... = about 2s (numbers are approximate for examples sake)