"Congrats on the 5DIV. Good to hear that it's better for BIF. I also purchased a 5DIV last month but have not had the chance to use it much. I will be putting my new 5DIV to the test next month when I travel to Southern California."
"Thanks everyone!. Same lens Robert (500F4 +1.4), but with the new 5d4. Getting more BIF keepers than with the 7dii. The increased resolution makes it almost on par with the 7dii, so it stays on my lens most of the time."
I ordered it through Henry’s in Halifax. I placed the order July 16, they told me it wouldn’t be delivered until the end of the year/new year (i.e. now), but it came in on Aug 28, so a month and a half wait.
The above was a quote from my friend who sold me the 500 and bought the 400mm DO.
I hope that helps.