I've been shooting with the 5D Mark III for a few days now. Mostly candid shots around the house and of the kids in the street. I've been shooting under gray skies through twilight. I'm used to shooting with my 5DII in these conditions, without a problem.
I'm finding that twilight shots are underexposed by 2/3 to 1 stop. I was shooting kids against asphalt, green bushes, and white garages. In all cases, they were underexposed. I bumped up my EC by 2/3, and 80% of the shots were right on, and 20% were 1/3 underexposed, as evidenced by the viewer, histogram, and reviewing them in post. Anyone else have this issue?