5D3 owners: What do you wish you knew?

HughHowey

EOS 80D
Mar 29, 2011
102
0
44
Boone, NC
www.hughhowey.com
My new body is "out for delivery." I've been reading the 404 page manual for the past few days, familiarizing myself with the settings and AF options. What do you wish you'd known the first day? Any customizations that you've found to make life easier? Here's your chance to impart your wisdom.

And not that anyone asked, but the 135L is going to be the first thing I slap on that puppy. :)