« on: June 02, 2013, 05:15:59 PM »
I have a Canon 5DIII and a Canon 600EX-RT and am using a 24-105L. I’m trying to take flash pictures of a backlit subject and bounce the flash of the ceiling. When I do this using full-auto the subject is exposed perfectly. When I try to take the same picture with the P (Program) setting , the subject comes out completely underexposed. I then tried hitting the mn-funtion button because I am told this will expose correctly for the center of the frame (no indication of any setting being saved in the viewfinder). No good, still completely under exposed. I tried sport metering, still under exposed. If I don’t bounce the flash the exposures are consistent between program and auto. I tried an old 580 flash and have the same problem so I know there is nothing wrong with the flash. My Question is why can’t I take pictures of backlit subjects and bounce the flash off the celling. Works great in Auto, terribly backlit of program mode.