Did not shoot the pics, but I suspect just a bit more sun and the automatic metering did the compensation. Don't see any shadow effects in the upper image, while the second has some obvious shadow. I.e. the sun was coming out. With wildlife, one rarely has time to do much in the way of manual work so she pretty much lets the camera do it's thing.
With the 100-400, she's using the older (like 4 or 5 yrs) EF 4.5 to 5.6 L IS that telescopes to zoom. Probably her favorite lens for wildlife. With something like the prime 500mm one often ends up too close to fit a critter into the frame, and that actually became an issue when the coyote came within 20 ft or so. Similarly, she started after the river deer with the 500, but came racing back to switch because the 500 could not even fit in the buck.
I believe the newer 100-400 does it's zooming internally as opposed to telescoping.
She can also get by hand holding the 100-400, but has to find a rest of some kind for the 500 prime. It's a pain in the butt chasing critters with big tripod in hand, although they are quite handy if one's working out of a blind. I can hand hold the prime, but I'm 6'4" with knuckles that near drag the ground. Lots of reach.
Also, remember the crop sensor cameras give one a 1.6 multiplier effect. I.e. Optically 100mm is equal to a 160mm and at 400mm it's the same as a 640mm on a full frame unit.
The 500 is essentially a fixed 800mm with a crop sensor. There are probably some folks around here that can explain things a bit more eloquently than I.
Last edited by 1minute; 12/09/16.
