Over my 1st 2 sessions wherein collection seemed to go fine the resulting image files (jpg and fit) appear to vary systematically in apparent exposure light & dark. The images have the same framing, etc and appear (visual inspection of images) to have the same information - they just appear to alternate light / dark on screen (image file sizes do not vary, just visual appearance.). Obvious & consistent pattern L/D/L/D - 50% of total are dark, 50% light - so it's not a reflection of variation in actual physical environment. Set up: guided 2 or 3 minute exposures using Canon 7D, RAW. Have not yet tried to post-process L/D images separately to determine if there is a functional difference. Similar experiences / explanation? Thank you.
