Thank you Jessica. Many folks on this forum (and others) appreciate you/Canon taking this issue seriously and working with us to address the problem. Periodic assurances work wonders.
If you have a handly link, we'd be happy to compare, but let's not muddy the water here. This IS a 5D3-specific issue and not a speedlight issue. I'm not saying your T3i does not have an issue or that your 430EX II doesn't have an issue, but clarit...
I finally had a chance to compare both my bodies (5D3 and T1i) with two flashes (600EX and 430EX II). I used the 40mm f2.8 for both (at first) with center point selected to keep things as consistent as possible. I shot into my walk-in closet, so it ...