So here's my problem. I already have a 6D, and mostly shoot slow moving wildlife, like bears, deer, elk, moose, and bison. My lenses range from the stealthy 200 2.8 (with a 2x) to the 100-400, Sigma 150-600, and now the Sigma 300-800 5.6 beast. I'm not a fan of swapping lenses in the field, and need a 2nd full frame camera. I can't decide between another 6D, or the 5D MKIII. Weight and price are not really big concerns. Sure, 50 extra focusing points should improve my ratio of keepers, but ISO performance (for higher shutter speeds) may help with that more. Just looking for someone that has shot both, or at least the 5D MK III, and can offer some insight.
Thanks!
I also shoot a lot of wildlife and used my 5d markIII. Bought a 7d mark II and highly recommend you take a look. AF system is the best Canon has does ports and wildlife and crop gives you some extra length. The 5d mark III is an amazing camera but the 7d mark II is the real deal for outdoors. I know there will be concerns on light sensitivity and indoors this a legitimate concern but do a search on images taken with it and I believe you'll be impressed with how it handles low light relative to any crop camera you've seen before.
Marc, thanks for the reply. I've actually already gotten another 6D, plus a pair of 7D bodies. At this point, I'm probably going to get another one of each, then wait and see what Canon comes out with in the next year or so.
Obviously you've made your decision by now. For the more general question I would have gone for the 5D Mark III. There's not a whole lot of image quality difference between the two, but the 5D III AF system is far more sophisticated than the 6D's and worth the price difference in my opinion. (In my experience the 5D Mark III AF system is also a bit more consistent than the 7D Mark II AF system.) Plus it never hurts to have two different models from the same generation of technology. For single camera applications you can select whichever one is best suited for a particular use case.
I chose the 6D for its superior AF over the 5D MKIII. When your subject moves little, or not at all, neither camera has an advantage. Until light levels drop. Then the 5D MKIII becomes a paperweight.