Hi,
Currently I am playing with the camera module. I am running raspistill in timelapse mode but I notice that the images are getting darker and darker during the time. I start the timelapse at 08:00 AM, image is great. The image at 09:00 AM however is quite dark and the image at 10:00 AM is quite ugly. If the camera module gives those dark images I can stop raspistill with ctrl-c and restart it, at that moment I have nice and bright image but one hour later the images gets darker and darker again. I take images once a minute but the first about 45 - 50 images look good but after that the images get darker, but the outdoor light circumstances get better....
I attached 3 images, with 1 hour difference in time from this morning. My command line is:
sudo raspistill --hflip --vflip -n -t 86400000 -tl 60000 -o image%d.jpg which I run as sudo from a mounted network share