After yesterday’s modest successes with BIF, I decided to really push my luck. I headed out on another sunny morning with the R, 600mm f/11, and RF 1.4X extender. Even at f/16, still life was no issue, though IQ took a small hit. BIF, well, it would track the all-white egrets but never got one with critical accuracy. On the contrastier purple heron, it nailed every shot with critical accuracy.
Surely the 90D, 100-400mm IS II, and EF Extender 1.4X III would outdo this. With that in mind, I headed out into a steamy 95-degree afternoon, again with bright sunshine. Trouble is, this brings loads of heat shimmer, especially over open fields.
The 90D supposedly has 27 focus points that work at f/8. One at a time, as in center point only, “they” worked fine. While tracking BIF with all 27 points, it would try to acquire only if I ballparked it manually first. With a card full of almost-but-not-quite shots, it didn’t get a single frame with critical accuracy, neither with egrets nor purple herons, against nor with the light. Shimmer could have affected the lower-flying critters, but not the overhead ones.
Had it been a contest, the EOS R, nearly earmarked for offloading a couple of days ago, would have won out today hands down. It’s not that I plan to chase BIF all that often; but I do like to know what I can count on, and to what level, whenever I set out to do it.
Canon marketing strikes again: “autofocus” vs. “autofocus accurately.” 😏
