Thanks Mike but I can't take credit. Lots of 70D users in this thread came to the conclusion
https://photography-on-the.net …ead.php?t=1442842&page=24
I did prove the issue for myself and yes - it underexposes. A user explained the issue - shipped it to Canon repair. Sent back to him not fixed. Repeated the whole process again with explicit explanation of the issue including sample shots as requested - plus his speedlight - and again it came back not fixed.
It would be helpful if Canon's top brass were politely nudged via the link to take corrective and just action.




