Here's a pretty nice review between the iPhone 6 and 6 Plus, also compared to the 5S, in regards to the camera and video capabilities. The photos and videos are great too:
http://austinmann.com/trek/iphone-6-...review-iceland
I haven't played much with my iPhone 6 Plus camera yet, but from the photos I've taken so far, the auto-exposure and fast auto-focus has been spot on.