I'm thinking of getting a 6D as a second body. I shoot mainly birds so I have a 7D Mark ii but I want something for everything else and I want it to be good in low light. I'd love to have a 5D Mark IV but it's way over my budget. I'm also thinking of the 80D because of the versatility. I don't care about video as I just shoot stills. I know these cameras are very different but I can't decide what to get. I have a T6i as the second body but I'm not that happy with it. I'd like to try photographing the milky way so that's why I was thinking about a full frame. Any advice would be great. Thanks.