I have used my new 5DMK iii for about three weeks so far. I spend most of the time shooting birds and other wildlife. I shoot mostly in AV with 7.1 aperture and iso of 800-1600 with a 100-400 canon lens. I have noticed that I have to add +2/3 to +1 EC for the photos to look right. The 7D that I just sold ran about +1/3 most of the time. My canon 60 gives good results at 0 EC. For those who have the 5DMKiii, do you have to add additional EC for your photos to come out correctly? I have used the 100-400 on the other camera bodies with no problems. As a side note, since I have started using the 5DMKiii for wildlife I very seldom use the 60D. I miss the reach but really like the photos that I have been getting.