Here's why.
These two shots were taken 0.3 sec apart in dense fog. I posted the first one in another thread a few days ago. They are processed and cropped slightly differently in PP because I pulled the second one out after re-visiting my shots for the trip. IMO the body posture and open mouth in the second frame make it a completely different image. Or is it just me?
Switching from one to the other in the light box really accentuates the differences.
NIKON D4, 200-400mm VR
f/5.6 @ 310 mm, 1/1000, ISO 6400