It WAS the exposure compensation! Didn't think to look there because I didn't change it, but somebody definitely did! Thanks so much for the help--the 6D is back to taking properly lit pix!!!
Thanks for your responses! I'm not using a flash. The lighting is sufficient for even my iPhone4 to capture images with no flash, but the 6D's images are dark.
Did you ever figure out what was going on? My 6D initially took great pix in AV mode in low-light, but I messed with some settings, and now all the images are dark unless I shoot manual--it's affecting all program modes. It's affecting the entire i...
