I am new to the forum, but someone asked if Canon had been contacted about the dark flash pictures. I have talked to Canon twice and they just kept telling me the exposure is based on the focusing point. I emailed 4 jpegs to their customer service and the reply was that they could not analyze the dark pictures because all of the data was not there as a jpeg and I was getting a replacement camera anyway. My first 20d underexposed by 2 stops. My replacement underexposes by only 1 stop...so I guess that's a little better.
I then sent 7 raw images to customer service. They looked at the first one, which was a person feeding a cat out of a white bowl. They said I chose the wrong exposure mode, center-weighted, instead of evaluative. Had they looked at the other images I sent, they would have seen that I also tried ALL of the exposure modes.
I'm not sure if I will keep the camera or not. I generally do not use the on board flash alot and the camera seems to work fine for non flash photography. I am less than thrilled with Canon's service at this point as well as the flash. I think 1/2 stop under may be acceptable, but 1-2 stops is not.
I will be emailing Canon support yet again.