I've been working on a project using the HQ camera where I want to take a small bitmap image (100x100), do some analysis on the bmp file, and using that information determine whether that exposure duration will be ok for my purpose. I needed to set the exposure mode to off because the AGC was messing with my results.
to do this, I would run a command like this in one of my scripts:
raspistill -e bmp -w 100 -h 100 -ex off -o sample.bmp -ss somenumber
Essentially what I've found is that there is a wide range of values for somenumber where the .bmp file has the normal .bmp header sections but the pixel array section is almost entirely 0. I've tested this with a wide range of lighting conditions, and I've found that for most values below 650000 I just don't get useful data.
Does anyone have an idea of what's going on here?